A similar notion was embodied in the celebrated medical theory called the

“Doctrine of Signatures,” “which is no less,” says Dr. Paris,(245) “than a

belief that every natural substance which possesses any medicinal virtue

indicates by an obvious and well-marked external character the disease for

which it is a remedy, or the object for which it should be employed.” This

outward character was generally some feature of resemblance, real or

fantastical, either to the effect it was supposed to produce, or to the

phenomenon over which its power was thought to be exercised. “Thus the

lungs of a fox must be a specific for asthma, because that animal is

remarkable for its strong powers of respiration. Turmeric has a brilliant

yellow color, which indicates that it has the power of curing the

jaundice; for the same reason, poppies must relieve diseases of the head;

Agaricus those of the bladder; _Cassia fistula_ the affections of the

intestines, and Aristolochia the disorders of the uterus: the polished

surface and stony hardness which so eminently characterize the seeds of

the Lithospermum officinale (common gromwell) were deemed a certain

indication of their efficacy in calculous and gravelly disorders; for a

similar reason, the roots of the Saxifraga granulata (white saxifrage)

gained reputation in the cure of the same disease; and the Euphrasia

(eye-bright) acquired fame, as an application in complaints of the eye,

because it exhibits a black spot in its corolla resembling the pupil. The

blood-stone, the Heliotropium of the ancients, from the occasional small

specks or points of a blood-red color exhibited on its green surface, is

even at this very day employed in many parts of England and Scotland to

stop a bleeding from the nose; and nettle tea continues a popular remedy

for the cure of _Urticaria_. It is also asserted that some substances bear

the _signatures_ of the humors, as the petals of the red rose that of the

blood, and the roots of rhubarb and the flowers of saffron that of the

bile.”

The early speculations respecting the chemical composition of bodies were

rendered abortive by no circumstance more than by their invariably taking

for granted that the properties of the elements must resemble those of the

compounds which were formed from them.

To descend to more modern instances; it was long thought, and was stoutly

maintained by the Cartesians and even by Leibnitz against the Newtonian

system (nor did Newton himself, as we have seen, contest the assumption,

but eluded it by an arbitrary hypothesis), that nothing (of a physical

nature at least) could account for motion, except previous motion; the

impulse or impact of some other body. It was very long before the

scientific world could prevail upon itself to admit attraction and

repulsion (_i.e._, spontaneous tendencies of particles to approach or

recede from one another) as ultimate laws, no more requiring to be

accounted for than impulse itself, if indeed the latter were not, in

truth, resolvable into the former. From the same source arose the

innumerable hypotheses devised to explain those classes of motion which

appeared more mysterious than others because there was no obvious mode of

attributing them to impulse, as for example the voluntary motions of the

human body. Such were the interminable systems of vibrations propagated

along the nerves, or animal spirits rushing up and down between the

muscles and the brain; which, if the facts could have been proved, would

have been an important addition to our knowledge of physiological laws;

but the mere invention, or arbitrary supposition of them, could not unless

by the strongest delusion be supposed to render the phenomena of animal

life more comprehensible, or less mysterious. Nothing, however, seemed

satisfactory, but to make out that motion was caused by motion; by

something like itself. If it was not one kind of motion, it must be

another. In like manner it was supposed that the physical qualities of

objects must arise from some similar quality, or perhaps only some quality

bearing the same name, in the particles or atoms of which the objects were

composed; that a sharp taste, for example, must arise from sharp

particles. And reversing the inference, the effects produced by a

phenomenon must, it was supposed, resemble in their physical attributes

the phenomenon itself. The influences of the planets were supposed to be

analogous to their visible peculiarities: Mars, being of a red color,

portended fire and slaughter; and the like.

Passing from physics to metaphysics, we may notice among the most

remarkable fruits of this _a priori_ fallacy two closely analogous

theories, employed in ancient and modern times to bridge over the chasm

between the world of mind and that of matter; the _species sensibiles_ of

the Epicureans, and the modern doctrine of perception by means of ideas.

These theories are indeed, probably, indebted for their existence not

solely to the fallacy in question, but to that fallacy combined with

another natural prejudice already adverted to, that a thing can not act

where it is not. In both doctrines it is assumed that the phenomenon which

takes place _in us_ when we see or touch an object, and which we regard as

an effect of that object, or rather of its presence to our organs, must of

necessity resemble very closely the outward object itself. To fulfill this

condition, the Epicureans supposed that objects were constantly projecting

in all directions impalpable images of themselves, which entered at the

eyes and penetrated to the mind; while modern metaphysicians, though they

rejected this hypothesis, agreed in deeming it necessary to suppose that

not the thing itself, but a mental image or representation of it, was the

direct object of perception. Dr. Reid had to employ a world of argument

and illustration to familiarize people with the truth, that the sensations

or impressions on our minds need not necessarily be copies of, or bear any

resemblance to, the causes which produce them; in opposition to the

natural prejudice which led people to assimilate the action of bodies upon

our senses, and through them upon our minds, to the transfer of a given

form from one object to another by actual moulding. The works of Dr. Reid

are even now the most effectual course of study for detaching the mind

from the prejudice of which this was an example. And the value of the

service which he thus rendered to popular philosophy is not much

diminished, although we may hold, with Brown, that he went too far in

imputing the “ideal theory” as an actual tenet, to the generality of the

philosophers who preceded him, and especially to Locke and Hume; for if

they did not themselves consciously fall into the error, unquestionably

they often led their readers into it.

The prejudice, that the conditions of a phenomenon must resemble the

phenomenon, is occasionally exaggerated, at least verbally, into a still

more palpable absurdity; the conditions of the thing are spoken of as if

they _were_ the very thing itself. In Bacon’s model inquiry, which

occupies so great a space in the _Novum Organum_, the _inquisitio in

formam calidi_, the conclusion which he favors is that heat is a kind of

motion; meaning of course not the feeling of heat, but the conditions of

the feeling; meaning, therefore, only that wherever there is heat, there

must first be a particular kind of motion; but he makes no distinction in

his language between these two ideas, expressing himself as if heat, and

the conditions of heat, were one and the same thing. So the elder Darwin,

in the beginning of his _Zoonomia_, says, “The word _idea_ has various

meanings in the writers of metaphysics; it is here used simply for those

notions of external things which our organs of sense bring us acquainted

with originally” (thus far the proposition, though vague, is

unexceptionable in meaning), “and is defined a contraction, a motion, or

configuration, of the fibres which constitute the immediate organ of

sense.” Our _notions_, a configuration of the fibres! What kind of

logician must he be who thinks that a phenomenon is _defined_ to _be_ the

condition on which he supposes it to depend? Accordingly he says soon

after, not that our ideas are caused by, or consequent on, certain organic

phenomena, but “our ideas _are_ animal motions of the organs of sense.”

And this confusion runs through the four volumes of the _Zoonomia_; the

reader never knows whether the writer is speaking of the effect, or of its

supposed cause; of the idea, a state of mental consciousness, or of the

state of the nerves and brain which he considers it to presuppose.

I have given a variety of instances in which the natural prejudice, that

causes and their effects must resemble one another, has operated in

practice so as to give rise to serious errors. I shall now go further, and

produce from writings even of the present or very recent times, instances

in which this prejudice is laid down as an established principle. M.

Victor Cousin, in the last of his celebrated lectures on Locke, enunciates

the maxim in the following unqualified terms: “Tout ce qui est vrai de

l’effet, est vrai de la cause.” A doctrine to which, unless in some

peculiar and technical meaning of the words cause and effect, it is not to

be imagined that any person would literally adhere; but he who could so

write must be far enough from seeing that the very reverse might be the

effect; that there is nothing impossible in the supposition that no one

property which is true of the effect might be true of the cause. Without

going quite so far in point of expression, Coleridge, in his _Biographia

Literaria_,(246) affirms as an “evident truth,” that “the law of causality

holds only between homogeneous things, _i.e._, things having some common

property,” and therefore “can not extend from one world into another, its

opposite;” hence, as mind and matter have no common property, mind can not

act upon matter, nor matter upon mind. What is this but the _a priori_

fallacy of which we are speaking? The doctrine, like many others of

Coleridge, is taken from Spinoza, in the first book of whose _Ethica_ (_De

Deo_) it stands as the Third Proposition, “Quæ res nihil commune inter se

habent, earum una alterius causa esse non potest,” and is there proved

from two so-called axioms, equally gratuitous with itself; but Spinoza

ever systematically consistent, pursued the doctrine to its inevitable

consequence, the materiality of God.

The same conception of impossibility led the ingenious and subtle mind of

Leibnitz to his celebrated doctrine of a pre-established harmony. He, too,

thought that mind could not act upon matter, nor matter upon mind, and

that the two, therefore, must have been arranged by their Maker like two

clocks, which, though unconnected with one another, strike simultaneously,

and always point to the same hour. Malebranche’s equally famous theory of

Occasional Causes was another form of the same conception; instead of

supposing the clocks originally arranged to strike together, he held that

when the one strikes, God interposes, and makes the other strike in

correspondence with it.

Descartes, in like manner, whose works are a rich mine of almost every

description of _a priori_ fallacy, says that the Efficient Cause must at

least have all the perfections of the effect, and for this singular

reason: “Si enim ponamus aliquid in ideâ reperiri quod non fuerit in ejus

causâ, hoc igitur habet a nihilo;” of which it is scarcely a parody to

say, that if there be pepper in the soup there must be pepper in the cook

who made it, since otherwise the pepper would be without a cause. A

similar fallacy is committed by Cicero, in his second book _De Finibus_,

where, speaking in his own person against the Epicureans, he charges them

with inconsistency in saying that the pleasures of the mind had their

origin from those of the body, and yet that the former were more valuable,

as if the effect could surpass the cause. “Animi voluptas oritur propter

voluptatem corporis, et major est animi voluptas quam corporis? ita fit ut

gratulator, lætior sit quam is cui gratulatur.” Even that, surely, is not

an impossibility; a person’s good fortune has often given more pleasure to

others than it gave to the person himself.

Descartes, with no less readiness, applies the same principle the converse

way, and infers the nature of the effects from the assumption that they

must, in this or that property or in all their properties, resemble their

cause. To this class belong his speculations, and those of so many others

after him, tending to infer the order of the universe, not from

observation, but by _a priori_ reasoning from supposed qualities of the

Godhead. This sort of inference was probably never carried to a greater

length than it was in one particular instance by Descartes, when, as a

proof of one of his physical principles, that the quantity of motion in

the universe is invariable, he had recourse to the immutability of the

Divine Nature. Reasoning of a very similar character is, however, nearly

as common now as it was in his time, and does duty largely as a means of

fencing off disagreeable conclusions. Writers have not yet ceased to

oppose the theory of divine benevolence to the evidence of physical facts,

to the principle of population for example. And people seem in general to

think that they have used a very powerful argument, when they have said,

that to suppose some proposition true, would be a reflection on the

goodness or wisdom of the Deity. Put into the simplest possible terms,

their argument is, “If it had depended on me, I would not have made the

proposition true, therefore it is not true.” Put into other words, it

stands thus: “God is perfect, therefore (what I think) perfection must

obtain in nature.” But since in reality every one feels that nature is

very far from perfect, the doctrine is never applied consistently. It

furnishes an argument which (like many others of a similar character)

people like to appeal to when it makes for their own side. Nobody is

convinced by it, but each appears to think that it puts religion on his

side of the question, and that it is a useful weapon of offense for

wounding an adversary.

Although several other varieties of _a priori_ fallacy might probably be

added to those here specified, these are all against which it seems

necessary to give any special caution. Our object is to open, without

attempting or affecting to exhaust, the subject. Having illustrated,

therefore, this first class of Fallacies at sufficient length, I shall

proceed to the second.

Chapter IV.

Fallacies Of Observation.

§ 1. From the Fallacies which are properly Prejudices, or presumptions

antecedent to, and superseding, proof, we pass to those which lie in the

incorrect performance of the proving process. And as Proof, in its widest

extent, embraces one or more, or all, of three processes, Observation,

Generalization, and Deduction, we shall consider in their order the errors

capable of being committed in these three operations. And first, of the

first mentioned.

A fallacy of misobservation may be either negative or positive; either

Non-observation or Mal-observation. It is non-observation, when all the

error consists in overlooking, or neglecting, facts or particulars which

ought to have been observed. It is mal-observation, when something is not

simply unseen, but seen wrong; when the fact or phenomenon, instead of

being recognized for what it is in reality, is mistaken for something

else.

§ 2. Non-observation may either take place by overlooking instances, or by

overlooking some of the circumstances of a given instance. If we were to

conclude that a fortune-teller was a true prophet, from not adverting to

the cases in which his predictions had been falsified by the event, this

would be non-observation of instances; but if we overlooked or remained

ignorant of the fact that in cases where the predictions had been

fulfilled, he had been in collusion with some one who had given him the

information on which they were grounded, this would be non-observation of

circumstances.

The former case, in so far as the act of induction from insufficient

evidence is concerned, does not fall under this second class of Fallacies,

but under the third, Fallacies of Generalization. In every such case,

however, there are two defects or errors instead of one; there is the

error of treating the insufficient evidence as if it were sufficient,

which is a Fallacy of the third class; and there is the insufficiency

itself; the not having better evidence; which, when such evidence, or, in

other words, when other instances, were to be had, is Non-observation; and

the erroneous inference, so far as it is to be attributed to this cause,

is a Fallacy of the second class.

It belongs not to our purpose to treat of non-observation as arising from

casual inattention, from general slovenliness of mental habits, want of

due practice in the use of the observing faculties, or insufficient

interest in the subject. The question pertinent to logic is—Granting the

want of complete competency in the observer, on what point is that

insufficiency on his part likely to lead him wrong? or rather, what sorts

of instances, or of circumstances in any given instance, are most likely

to escape the notice of observers generally; of mankind at large.

§ 3. First, then, it is evident that when the instances on one side of a

question are more likely to be remembered and recorded than those on the

other; especially if there be any strong motive to preserve the memory of

the first, but not of the latter; these last are likely to be overlooked,

and escape the observation of the mass of mankind. This is the recognized

explanation of the credit given, in spite of reason and evidence, to many

classes of impostors; to quack-doctors, and fortune-tellers in all ages;

to the “cunning man” of modern times, and the oracles of old. Few have

considered the extent to which this fallacy operates in practice, even in

the teeth of the most palpable negative evidence. A striking example of it

is the faith which the uneducated portion of the agricultural classes, in

this and other countries, continue to repose in the prophecies as to

weather supplied by almanac-makers; though every season affords to them

numerous cases of completely erroneous prediction; but as every season

also furnishes some cases in which the prediction is fulfilled, this is

enough to keep up the credit of the prophet, with people who do not

reflect on the number of instances requisite for what we have called, in

our inductive terminology, the Elimination of Chance; since a certain

number of casual coincidences not only may but will happen, between any

two unconnected events.

Coleridge, in one of the essays in the _Friend_, has illustrated the

matter we are now considering, in discussing the origin of a proverb,

“which, differently worded, is to be found in all the languages of

Europe,” viz., “Fortune favors fools.” He ascribes it partly to the

“tendency to exaggerate all effects that seem disproportionate to their

visible cause, and all circumstances that are in any way strongly

contrasted with our notions of the persons under them.” Omitting some

explanations which would refer the error to mal-observation, or to the

other species of non-observation (that of circumstances), I take up the

quotation further on. “Unforeseen coincidences may have greatly helped a

man, yet if they have done for him only what possibly from his own

abilities he might have effected for himself, his good luck will excite

less attention, and the instances be less remembered. That clever men

should attain their objects seems natural, and we neglect the

circumstances that perhaps produced that success of themselves without the

intervention of skill or foresight; but we dwell on the fact and remember

it, as something strange, when the same happens to a weak or ignorant man.

So too, though the latter should fail in his undertakings from

concurrences that might have happened to the wisest man, yet his failure

being no more than might have been expected and accounted for from his

folly, it lays no hold on our attention, but fleets away among the other

undistinguished waves in which the stream of ordinary life murmurs by us,

and is forgotten. Had it been as true as it was notoriously false, that

those all-embracing discoveries, which have shed a dawn of _science_ on

the _art_ of chemistry, and give no obscure promise of some one great

constitutive law, in the light of which dwell dominion and the power of

prophecy; if these discoveries, instead of having been, as they really

were, preconcerted by meditation, and evolved out of his own intellect,

had occurred by a set of lucky _accidents_ to the illustrious father and

founder of philosophic alchemy; if they had presented themselves to

Professor Davy exclusively in consequence of his _luck_ in possessing a

particular galvanic battery; if this battery, as far as Davy was

concerned, had itself been an _accident_, and not (as in point of fact it

was) desired and obtained by him for the purpose of insuring the testimony

of experience to his principles, and in order to bind down material nature

under the inquisition of reason, and force from her, as by torture,

unequivocal answers to _prepared_ and _preconceived_ questions—yet still

they would not have been talked of or described as instances of _luck_,

but as the natural results of his admitted genius and known skill. But

should an accident have disclosed similar discoveries to a mechanic at

Birmingham or Sheffield, and if the man should grow rich in consequence,

and partly by the envy of his neighbors and partly with good reason, be

considered by them as a man _below par_ in the general powers of his

understanding; then, ‘Oh, what a lucky fellow! Well, Fortune _does_ favor

fools—that’s for certain! It is always so!’ And forthwith the exclaimer

relates half a dozen similar instances. Thus accumulating the one sort of

facts and never collecting the other, we do, as poets in their diction,

and quacks of all denominations do in their reasoning, put a part for the

whole.”

This passage very happily sets forth the manner in which, under the loose

mode of induction which proceeds _per enumerationem simplicem_, not

seeking for instances of such a kind as to be decisive of the question,

but generalizing from any which occur, or rather which are remembered,

opinions grow up with the apparent sanction of experience, which have no

foundation in the laws of nature at all. “Itaque recte respondit ille” (we

may say with Bacon(247)), “qui cum suspensa tabula in templo ei

monstraretur eorum, qui vota solverant, quod naufragii periculo elapsi

sint, atque interrogando premeretur, anne tum quidem Deorum numen

agnosceret, quæsivit denuo, _At ubi sunt illi depicti qui post vota

nuncupata perierunt_? Eadem ratio est fere omnis superstitionis, ut in

Astrologicis, in Somniis, Ominibus, Nemesibus, et hujusmodi; in quibus,

homines delectati hujusmodi vanitatibus, advertunt eventus, ubi implentur;

ast ubi fallunt, licet multo frequentius, tamen negligunt, et prætereunt.”

And he proceeds to say that, independently of the love of the marvelous,

or any other bias in the inclinations, there is a natural tendency in the

intellect itself to this kind of fallacy; since the mind is more moved by

affirmative instances, though negative ones are of most use in philosophy:

“Is tamen humano intellectui error est proprius et perpetuus, ut magis

moveatur et excitetur Affirmativis quam Negativis; cum rite et ordine

æquum se utrique præbere debeat; quin contra, in omni Axiomate vero

constituendo, major vis est instantiæ negativæ.”

But the greatest of all causes of non-observation is a preconceived

opinion. This it is which, in all ages, has made the whole race of

mankind, and every separate section of it, for the most part unobservant

of all facts, however abundant, even when passing under their own eyes,

which are contradictory to any first appearance, or any received tenet. It

is worth while to recall occasionally to the oblivious memory of mankind

some of the striking instances in which opinions that the simplest

experiment would have shown to be erroneous, continued to be entertained

because nobody ever thought of trying that experiment. One of the most

remarkable of these was exhibited in the Copernican controversy. The

opponents of Copernicus argued that the earth did not move, because if it

did, a stone let fall from the top of a high tower would not reach the

ground at the foot of the tower, but at a little distance from it, in a

contrary direction to the earth’s course; in the same manner (said they)

as, if a ball is let drop from the mast-head while the ship is in full

sail, it does not fall exactly at the foot of the mast, but nearer to the

stern of the vessel. The Copernicans would have silenced these objectors

at once if they had _tried_ dropping a ball from the mast-head, since they

would have found that it does fall exactly at the foot, as the theory

requires; but no; they admitted the spurious fact, and struggled vainly to

make out a difference between the two cases. “The ball was no _part_ of

the ship—and the motion forward was not _natural_, either to the ship or

to the ball. The stone, on the other hand, let fall from the top of the

tower, was a _part_ of the earth; and therefore, the diurnal and annular

revolutions which were _natural_ to the earth, were also _natural_ to the

stone; the stone would, therefore, retain the same motion with the tower,

and strike the ground precisely at the bottom of it.”(248)

Other examples, scarcely less striking, are recorded by Dr. Whewell,(249)

where imaginary laws of nature have continued to be received as real,

merely because no person had steadily looked at facts which almost every

one had the opportunity of observing. “A vague and loose mode of looking

at facts very easily observable, left men for a long time under the belief

that a body ten times as heavy as another falls ten times as fast; that

objects immersed in water are always magnified, without regard to the form

of the surface; that the magnet exerts an irresistible force; that crystal

is always found associated with ice; and the like. These and many others

are examples how blind and careless man can be even in observation of the

plainest and commonest appearances; and they show us that the mere

faculties of perception, although constantly exercised upon innumerable

objects, may long fail in leading to any exact knowledge.”

If even on physical facts, and these of the most obvious character, the

observing faculties of mankind can be to this degree the passive slaves of

their preconceived impressions, we need not be surprised that this should

be so lamentably true as all experience attests it to be, on things more

nearly connected with their stronger feelings—on moral, social, and

religious subjects. The information which an ordinary traveler brings back

from a foreign country, as the result of the evidence of his senses, is

almost always such as exactly confirms the opinions with which he set out.

He has had eyes and ears for such things only as he expected to see. Men

read the sacred books of their religion, and pass unobserved therein

multitudes of things utterly irreconcilable with even their own notions of

moral excellence. With the same authorities before them, different

historians, alike innocent of intentional misrepresentation, see only what

is favorable to Protestants or Catholics, royalists or republicans,

Charles I. or Cromwell; while others, having set out with the

preconception that extremes must be in the wrong, are incapable of seeing

truth and justice when these are wholly on one side.

The influence of a preconceived theory is well exemplified in the

superstitions of barbarians respecting the virtues of medicaments and

charms. The negroes, among whom coral, as of old among ourselves, is worn

as an amulet, affirm, according to Dr. Paris,(250) that its color “is

always affected by the state of health of the wearer, it becoming paler in

disease.” On a matter open to universal observation, a general proposition

which has not the smallest vestige of truth is received as a result of

experience; the preconceived opinion preventing, it would seem, any

observation whatever on the subject.

§ 4. For illustration of the first species of non-observation, that of

Instances, what has now been stated may suffice. But there may also be

non-observation of some material circumstances, in instances which have

not been altogether overlooked—nay, which may be the very instances on

which the whole superstructure of a theory has been founded. As, in the

cases hitherto examined, a general proposition was too rashly adopted, on

the evidence of particulars, true indeed, but insufficient to support it;

so in the cases to which we now turn, the particulars themselves have been

imperfectly observed, and the singular propositions on which the

generalization is grounded, or some at least of those singular

propositions, are false.

Such, for instance, was one of the mistakes committed in the celebrated

phlogistic theory; a doctrine which accounted for combustion by the

extrication of a substance called phlogiston, supposed to be contained in

all combustible matter. The hypothesis accorded tolerably well with

superficial appearances; the ascent of flame naturally suggests the escape

of a substance; and the visible residuum of ashes, in bulk and weight,

generally falls extremely short of the combustible material. The error

was, non-observation of an important portion of the actual residue,

namely, the gaseous products of combustion. When these were at last

noticed and brought into account, it appeared to be a universal law, that

all substances gain instead of losing weight by undergoing combustion; and

after the usual attempt to accommodate the old theory to the new fact by

means of an arbitrary hypothesis (that phlogiston had the quality of

positive levity instead of gravity), chemists were conducted to the true

explanation, namely, that instead of a substance separated, there was, on

the contrary, a substance absorbed.

Many of the absurd practices which have been deemed to possess medicinal

efficacy, have been indebted for their reputation to non-observance of

some accompanying circumstance which was the real agent in the cures

ascribed to them. Thus, of the sympathetic powder of Sir Kenelm Digby:

“Whenever any wound had been inflicted, this powder was applied to the

weapon that had inflicted it, which was, moreover, covered with ointment,

and dressed two or three times a day. The wound itself, in the mean time,

was directed to be brought together, and carefully bound up with clean

linen rags, but, _above all, to be let alone_ for seven days, at the end

of which period the bandages were removed, when the wound was generally

found perfectly united. The triumph of the cure was decreed to the

mysterious agency of the sympathetic powder which had been so assiduously

applied to the weapon, whereas it is hardly necessary to observe that the

promptness of the cure depended on the total exclusion of air from the

wound, and upon the sanative operations of nature not having received any

disturbance from the officious interference of art. The result, beyond all

doubt, furnished the first hint which led surgeons to the improved

practice of healing wounds by what is technically called the _first

intention_.”(251) “In all records,” adds Dr. Paris, of “extraordinary

cures performed by mysterious agents, there is a great desire to conceal

the remedies and other curative means which were simultaneously

administered with them; thus Oribasius commends in high terms a necklace

of Pæony root for the cure of epilepsy; but we learn that he always took

care to accompany its use with copious evacuations, although he assigns to

them no share of credit in the cure. In later times we have a good

specimen of this species of deception, presented to us in a work on

scrofula by Mr. Morley, written, as we are informed, for the sole purpose

of restoring the much-injured character and use of the Vervain; in which

the author directs the root of this plant to be tied with a yard of white

satin ribbon around the neck, where it is to remain until the patient is

cured; but mark—during this interval he calls to his aid the most active

medicines in the materia medica.”(252)

In other cases, the cures really produced by rest, regimen, and amusement

have been ascribed to the medicinal, or occasionally to the supernatural,

means which were put in requisition. “The celebrated John Wesley, while he

commemorates the triumph of sulphur and supplication over his bodily

infirmity, forgets to appreciate the resuscitating influence of four

months’ repose from his apostolic labors; and such is the disposition of

the human mind to place confidence in the operation of mysterious agents,

that we find him more disposed to attribute his cure to a brown paper

plaster of egg and brimstone, than to Dr. Fothergill’s salutary

prescription of country air, rest, asses’ milk, and horse exercise.”(253)

In the following example, the circumstance overlooked was of a somewhat

different character. “When the yellow fever raged in America, the

practitioners trusted exclusively to the copious use of mercury; at first

this plan was deemed so universally efficacious, that, in the enthusiasm

of the moment, it was triumphantly proclaimed that death never took place

after the mercury had evinced its effect upon the system: all this was

very true, but it furnished no proof of the efficacy of that metal, since

the disease in its aggravated form was so rapid in its career, that it

swept away its victims long before the system could be brought under

mercurial influence, while in its milder shape it passed off equally well

without any assistance from art.”(254)

In these examples the circumstance overlooked was cognizable by the

senses. In other cases, it is one the knowledge of which could only be

arrived at by reasoning; but the fallacy may still be classed under the

head to which, for want of a more appropriate name, we have given the

appellation Fallacies of Non-observation. It is not the nature of the

faculties which ought to have been employed, but the non-employment of

them, which constitutes this Natural Order of Fallacies. Wherever the

error is negative, not positive; wherever it consists especially in

_overlooking_, in being ignorant or unmindful of some fact which, if known

and attended to, would have made a difference in the conclusion arrived

at; the error is properly placed in the Class which we are considering. In

this Class, there is not, as in all other fallacies there is, a positive

misestimate of evidence actually had. The conclusion would be just, if the

portion which is seen of the case were the whole of it; but there is

another portion overlooked, which vitiates the result.

For instance, there is a remarkable doctrine which has occasionally found

a vent in the public speeches of unwise legislators, but which only in one

instance that I am aware of has received the sanction of a philosophical

writer, namely, M. Cousin, who in his preface to the _Gorgias_ of Plato,

contending that punishment must have some other and higher justification

than the prevention of crime, makes use of this argument—that if

punishment were only for the sake of example, it would be indifferent

whether we punished the innocent or the guilty, since the punishment,

considered as an example, is equally efficacious in either case. Now we

must, in order to go along with this reasoning, suppose, that the person

who feels himself under temptation, observing somebody punished, concludes

himself to be in danger of being punished likewise, and is terrified

accordingly. But it is forgotten that if the person punished is supposed

to be innocent, or even if there be any doubt of his guilt, the spectator

will reflect that his own danger, whatever it may be, is not contingent on

his guiltiness, but threatens him equally if he remains innocent, and how,

therefore, is he deterred from guilt by the apprehension of such

punishment? M. Cousin supposes that people will be dissuaded from guilt by

whatever renders the condition of the guilty more perilous, forgetting

that the condition of the innocent (also one of the elements in the

calculation) is, in the case supposed, made perilous in precisely an equal

degree. This is a fallacy of overlooking; or of non-observation, within

the intent of our classification.

Fallacies of this description are the great stumbling-block to correct

thinking in political economy. The economical workings of society afford

numerous cases in which the effects of a cause consist of two sets of

phenomena: the one immediate, concentrated, obvious to all eyes, and

passing, in common apprehension, for the whole effect; the other widely

diffused, or lying deeper under the surface, and which is exactly contrary

to the former. Take, for instance, the common notion so plausible at the

first glance, of the encouragement given to industry by lavish

expenditure. A, who spends his whole income, and even his capital, in

expensive living, is supposed to give great employment to labor. B, who

lives on a small portion, and invests the remainder in the funds, is

thought to give little or no employment. For every body sees the gains

which are made by A’s tradesmen, servants, and others, while his money is

spending. B’s savings, on the contrary, pass into the hands of the person

whose stock he purchased, who with it pays a debt he owed to some banker,

who lends it again to some merchant or manufacturer; and the capital being

laid out in hiring spinners and weavers, or carriers and the crews of

merchant vessels, not only gives immediate employment to at least as much

industry as A employs during the whole of his career, but coming back with

increase by the sale of the goods which have been manufactured or

imported, forms a fund for the employment of the same and perhaps a

greater quantity of labor in perpetuity. But the observer does not see,

and therefore does not consider, what becomes of B’s money; he does see

what is done with A’s; he observes the amount of industry which A’s

profusion feeds; he observes not the far greater quantity which it

prevents from being fed; and thence the prejudice, universal to the time

of Adam Smith, that prodigality encourages industry, and parsimony is a

discouragement to it.

The common argument against free trade was a fallacy of the same nature.

The purchaser of British silk encourages British industry; the purchaser

of Lyons silk encourages only French; the former conduct is patriotic, the

latter ought to be prevented by law. The circumstance is overlooked, that

the purchaser of any foreign commodity necessarily causes, directly or

indirectly, the export of an equivalent value of some article of home

production (beyond what would otherwise be exported), either to the same

foreign country or to some other; which fact, though from the complication

of the circumstances it can not always be verified by specific

observation, no observation can possibly be brought to contradict, while

the evidence of reasoning on which it rests is irrefragable. The fallacy

is, therefore, the same as in the preceding case, that of seeing a part

only of the phenomena, and imagining that part to be the whole; and may be

ranked among Fallacies of Non-observation.

§ 5. To complete the examination of the second of our five classes, we

have now to speak of Mal-observation; in which the error does not lie in

the fact that something is unseen, but that something seen is seen wrong.

Perception being infallible evidence of whatever is really perceived, the

error now under consideration can be committed no otherwise than by

mistaking for conception what is, in fact, inference. We have formerly

shown how intimately the two are blended in almost every thing which is

called observation, and still more in every Description.(255) What is

actually on any occasion perceived by our senses being so minute in

amount, and generally so unimportant a portion of the state of facts which

we wish to ascertain or to communicate; it would be absurd to say that

either in our observations, or in conveying their result to others, we

ought not to mingle inference with fact; all that can be said is, that

when we do so we ought to be aware of what we are doing, and to know what

part of the assertion rests on consciousness, and is therefore

indisputable, what part on inference, and is therefore questionable.

One of the most celebrated examples of a universal error produced by

mistaking an inference for the direct evidence of the senses, was the

resistance made, on the ground of common sense, to the Copernican system.

People fancied they _saw_ the sun rise and set, the stars revolve in

circles round the pole. We now know that they saw no such thing; what they

really saw was a set of appearances, equally reconcilable with the theory

they held and with a totally different one. It seems strange that such an

instance as this of the testimony of the senses pleaded with the most

entire conviction in favor of something which was a mere inference of the

judgment, and, as it turned out, a false inference, should not have opened

the eyes of the bigots of common sense, and inspired them with a more

modest distrust of the competency of mere ignorance to judge the

conclusions of cultivated thought.

In proportion to any person’s deficiency of knowledge and mental

cultivation is, generally, his inability to discriminate between his

inferences and the perceptions on which they were grounded. Many a

marvelous tale, many a scandalous anecdote, owes its origin to this

incapacity. The narrator relates, not what he saw or heard, but the

impression which he derived from what he saw or heard, and of which

perhaps the greater part consisted of inference, though the whole is

related, not as inference but as matter of fact. The difficulty of

inducing witnesses to restrain within any moderate limits the intermixture

of their inferences with the narrative of their perceptions, is well known

to experienced cross-examiners; and still more is this the case when

ignorant persons attempt to describe any natural phenomenon. “The simplest

narrative,” says Dugald Stewart,(256) “of the most illiterate observer

involves more or less of hypothesis; nay, in general, it will be found

that, in proportion to his ignorance, the greater is the number of

conjectural principles involved in his statements. A village apothecary

(and, if possible, in a still greater degree, an experienced nurse) is

seldom able to describe the plainest case, without employing a phraseology

of which every word is a theory: whereas a simple and genuine

specification of the phenomena which mark a particular disease; a

specification unsophisticated by fancy, or by preconceived opinions, may

be regarded as unequivocal evidence of a mind trained by long and

successful study to the most difficult of all arts, that of the faithful

_interpretation_ of nature.”

The universality of the confusion between perceptions and the inferences

drawn from them, and the rarity of the power to discriminate the one from

the other, ceases to surprise us when we consider that in the far greater

number of instances the actual perceptions of our senses are of no

importance or interest to us except as marks from which we infer something

beyond them. It is not the color and superficial extension perceived by

the eye that are important to us, but the object, of which those visible

appearances testify the presence; and where the sensation itself is

indifferent, as it generally is, we have no motive to attend particularly

to it, but acquire a habit of passing it over without distinct

consciousness, and going on at once to the inference. So that to know what

the sensation actually was, is a study in itself, to which painters, for

example, have to train themselves by special and long-continued discipline

and application. In things farther removed from the dominion of the

outward senses, no one who has not great experience in psychological

analysis is competent to break this intense association; and when such

analytic habits do not exist in the requisite degree, it is hardly

possible to mention any of the habitual judgments of mankind on subjects

of a high degree of abstraction, from the being of a God and the

immortality of the soul down to the multiplication table, which are not,

or have not been, considered as matter of direct intuition. So strong is

the tendency to ascribe an intuitive character to judgments which are mere

inferences, and often false ones. No one can doubt that many a deluded

visionary has actually believed that he was directly inspired from Heaven,

and that the Almighty had conversed with him face to face; which yet was

only, on his part, a conclusion drawn from appearances to his senses, or

feelings in his internal consciousness, which afforded no warrant for any

such belief. A caution, therefore, against this class of errors, is not

only needful but indispensable; though to determine whether, on any of the

great questions of metaphysics, such errors are actually committed,

belongs not to this place, but, as I have so often said, to a different

science.

Chapter V.

Fallacies Of Generalization.

§ 1. The class of Fallacies of which we are now to speak, is the most

extensive of all; embracing a greater number and variety of unfounded

inferences than any of the other classes, and which it is even more

difficult to reduce to sub-classes or species. If the attempt made in the

preceding books to define the principles of well-grounded generalization

has been successful, all generalizations not conformable to those

principles might, in a certain sense, be brought under the present class;

when, however, the rules are known and kept in view, but a casual lapse

committed in the application of them, this is a blunder, not a fallacy. To

entitle an error of generalization to the latter epithet, it must be

committed on principle; there must lie in it some erroneous general

conception of the inductive process; the legitimate mode of drawing

conclusions from observation and experiment must be fundamentally

misconceived.

Without attempting any thing so chimerical as an exhaustive classification

of all the misconceptions which can exist on the subject, let us content

ourselves with noting, among the cautions which might be suggested, a few

of the most useful and needful.

§ 2. In the first place, there are certain kinds of generalization which,

if the principles already laid down be correct, _must_ be groundless;

experience can not afford the necessary conditions for establishing them

by a correct induction. Such, for instance, are all inferences from the

order of nature existing on the earth, or in the solar system, to that

which may exist in remote parts of the universe; where the phenomena, for

aught we know, may be entirely different, or may succeed one another

according to different laws, or even according to no fixed law at all.

Such, again, in matters dependent on causation, are all universal

negatives, all propositions that assert impossibility. The non-existence

of any given phenomenon, however uniformly experience may as yet have

testified to the fact, proves at most that no cause, adequate to its

production, has yet manifested itself; but that no such causes exist in

nature can only be inferred if we are so foolish as to suppose that we

know all the forces in nature. The supposition would at least be premature

while our acquaintance with some even of those which we do know is so

extremely recent. And however much our knowledge of nature may hereafter

be extended, it is not easy to see how that knowledge could ever be

complete, or how, if it were, we could ever be assured of its being so.

The only laws of nature which afford sufficient warrant for attributing

impossibility (even with reference to the existing order of nature, and to

our own region of the universe) are, first, those of number and extension,

which are paramount to the laws of the succession of phenomena, and not

exposed to the agency of counteracting causes; and, secondly, the

universal law of causality itself. That no valuation in any effect or

consequent will take place while the whole of the antecedents remain the

same, may be affirmed with full assurance. But, that the addition of some

new antecedent might not entirely alter and subvert the accustomed

consequent, or that antecedents competent to do this do not exist in

nature, we are in no case empowered positively to conclude.

§ 3. It is next to be remarked that all generalizations which profess,

like the theories of Thales, Democritus, and others of the early Greek

speculators, to resolve all things into some one element, or like many

modern theories, to resolve phenomena radically different into the same,

are necessarily false. By radically different phenomena I mean impressions

on our senses which differ in quality, and not merely in degree. On this

subject what appeared necessary was said in the chapter on the Limits to

the Explanation of Laws of Nature; but as the fallacy is even in our own

times a common one, I shall touch on it somewhat further in this place.

When we say that the force which retains the planets in their orbits is

resolved into gravity, or that the force which makes substances combine

chemically is resolved into electricity, we assert in the one case what

is, and in the other case what might, and probably will ultimately, be a

legitimate result of induction. In both these cases motion is resolved

into motion. The assertion is, that a case of motion, which was supposed

to be special, and to follow a distinct law of its own, conforms to and is

included in the general law which regulates another class of motions. But,

from these and similar generalizations, countenance and currency have been

given to attempts to resolve, not motion into motion, but heat into

motion, light into motion, sensation itself into motion; states of

consciousness into states of the nervous system, as in the ruder forms of

the materialist philosophy; vital phenomena into mechanical or chemical

processes, as in some schools of physiology.

Now I am far from pretending that it may not be capable of proof, or that

it is not an important addition to our knowledge if proved, that certain

motions in the particles of bodies are the _conditions_ of the production

of heat or light; that certain assignable physical modifications of the

nerves may be the conditions not only of our sensations or emotions, but

even of our thoughts; that certain mechanical and chemical conditions may,

in the order of nature, be sufficient to determine to action the

physiological laws of life. All I insist upon, in common with every

thinker who entertains any clear idea of the logic of science, is, that it

shall not be supposed that by proving these things one step would be made

toward a real explanation of heat, light, or sensation; or that the

generic peculiarity of those phenomena can be in the least degree evaded

by any such discoveries, however well established. Let it be shown, for

instance, that the most complex series of physical causes and effects

succeed one another in the eye and in the brain to produce a sensation of

color; rays falling on the eye, refracted, converging, crossing one

another, making an inverted image on the retina, and after this a

motion—let it be a vibration, or a rush of nervous fluid, or whatever else

you are pleased to suppose, along the optic nerve—a propagation of this

motion to the brain itself, and as many more different motions as you

choose; still, at the end of these motions, there is something which is

not motion, there is a feeling or sensation of color. Whatever number of

motions we may be able to interpolate, and whether they be real or

imaginary, we shall still find, at the end of the series, a motion

antecedent and a color consequent. The mode in which any one of the

motions produces the next, may possibly be susceptible of explanation by

some general law of motion: but the mode in which the last motion produces

the sensation of color, can not be explained by any law of motion; it is

the law of color: which is, and must always remain, a peculiar thing.

Where our consciousness recognizes between two phenomena an inherent

distinction; where we are sensible of a difference which is not merely of

degree, and feel that no adding one of the phenomena to itself would

produce the other; any theory which attempts to bring either under the

laws of the other must be false; though a theory which merely treats the

one as a cause or condition of the other, may possibly be true.

§ 4. Among the remaining forms of erroneous generalization, several of

those most worthy of and most requiring notice have fallen under our

examination in former places, where, in investigating the rules of correct

induction, we have had occasion to advert to the distinction between it

and some common mode of the incorrect. In this number is what I have

formerly called the natural Induction of uninquiring minds, the induction

of the ancients, which proceeds _per enumerationem simplicem_: “This,

that, and the other A are B, I can not think of any A which is not B,

therefore every A is B.” As a final condemnation of this rude and slovenly

mode of generalization, I will quote Bacon’s emphatic denunciation of it;

the most important part, as I have more than once ventured to assert, of

the permanent service rendered by him to philosophy. “Inductio quæ

procedit per enumerationem simplicem, res puerilis est, et precario

concludit” (concludes only _by your leave_, or provisionally), “et

periculo exponitur ab instantiâ contradictoriâ, et plerumque secundum

pauciora quam par est, et _ex his tantummodo quæ præsto sunt pronunciat_.

At Inductio quæ ad inventionem et demonstrationem Scientiarum et Artium

erit utilis, Naturam separare debet, per rejectiones et exclusiones

debitas; ac deinde post negativas tot quot sufficiunt, super affirmativas

concludere.”

I have already said that the mode of Simple Enumeration is still the

common and received method of Induction in whatever relates to man and

society. Of this a very few instances, more by way of memento than of

instruction, may suffice. What, for example, is to be thought of all the

“common-sense” maxims for which the following may serve as the universal

formula, “Whatsoever has never been, will never be.” As for example:

negroes have never been as civilized as whites sometimes are, therefore it

is impossible they should be so. Women, as a class, are supposed not to

have hitherto been equal in intellect to men, therefore they are

necessarily inferior. Society can not prosper without this or the other

institution; _e.g._, in Aristotle’s time, without slavery; in later times,

without an established priesthood, without artificial distinctions of

rank, etc. One poor person in a thousand, educated, while the nine hundred

and ninety-nine remain uneducated, has usually aimed at raising himself

out of his class, therefore education makes people dissatisfied with the

condition of a laborer. Bookish men, taken from speculative pursuits and

set to work on something they know nothing about, have generally been

found or thought to do it ill; therefore philosophers are unfit for

business, etc., etc. All these are inductions by simple enumeration.

Reasons having some reference to the canons of scientific investigation

have been attempted to be given, however unsuccessfully, for some of these

propositions; but to the multitude of those who parrot them, the

_enumeratio simplex, ex __ his tantummodo quæ præsto sunt pronuncians_, is

the sole evidence. Their fallacy consists in this, that they are

inductions without elimination: there has been no real comparison of

instances, nor even ascertainment of the material facts in any given

instance. There is also the further error, of forgetting that such

generalizations, even if well established, could not be ultimate truths,

but must be results of laws much more elementary; and therefore, until

deduced from such, could at most be admitted as empirical laws, holding

good within the limits of space and time by which the particular

observations that suggested the generalization were bounded.

This error, of placing mere empirical laws, and laws in which there is no

direct evidence of causation, on the same footing of certainty as laws of

cause and effect, an error which is at the root of perhaps the greater

number of bad inductions, is exemplified only in its grossest form in the

kind of generalizations to which we have now referred. These, indeed, do

not possess even the degree of evidence which pertains to a

well-ascertained empirical law; but admit of refutation on the empirical

ground itself, without ascending to casual laws. A little reflection,

indeed, will show that mere negations can only form the ground of the

lowest and least valuable kind of empirical law. A phenomenon has never

been noticed; this only proves that the conditions of that phenomenon have

not yet occurred in experience, but does not prove that they may not occur

hereafter. There is a better kind of empirical law than this, namely, when

a phenomenon which is observed presents within the limits of observation a

series of gradations, in which a regularity, or something like a

mathematical law, is perceptible; from which, therefore, something may be

rationally presumed as to those terms of the series which are beyond the

limits of observation. But in negation there are no gradations, and no

series; the generalizations, therefore, which deny the possibility of any

given condition of man and society merely because it has never yet been

witnessed, can not possess this higher degree of validity even as

empirical laws. What is more, the minuter examination which that higher

order of empirical laws presupposes, being applied to the subject-matter

of these, not only does not confirm but actually refutes them. For in

reality the past history of Man and Society, instead of exhibiting them as

immovable, unchangeable, incapable of ever presenting new phenomena, shows

them, on the contrary, to be, in many most important particulars, not only

changeable, but actually undergoing a progressive change. The empirical

law, therefore, best expressive, in most cases, of the genuine result of

observation, would be, not that such and such a phenomenon will continue

unchanged, but that it will continue to change in some particular manner.

Accordingly, while almost all generalizations relating to Man and Society,

antecedent to the last fifty or sixty years, have erred in the gross way

which we have attempted to characterize, namely, by implicitly assuming

that nature and society will forever revolve in the same orbit, and

exhibit essentially the same phenomena; which is also the vulgar error of

the ostentatiously practical, the votaries of so-called common sense, in

our day, especially in Great Britain; the more thinking minds of the

present age, having applied a more minute analysis to the past records of

our race, have for the most part adopted a contrary opinion, that the

human species is in a state of necessary progression, and that from the

terms of the series which are past we may infer positively those which are

yet to come. Of this doctrine, considered as a philosophical tenet, we

shall have occasion to speak more fully in the concluding Book. If not, in

all its forms, free from error, it is at least free from the gross and

error which we previously exemplified. But, in all except the most

eminently philosophical minds, it is infected with precisely the same

_kind_ of fallacy as that is. For we must remember that even this other

and better generalization, the progressive change in the condition of the

human species, is, after all, but an empirical law; to which, too, it is

not difficult to point out exceedingly large exceptions; and even if these

could be got rid of, either by disputing the facts or by explaining and

limiting the theory, the general objection remains valid against the

supposed law, as applicable to any other than what, in our third book,

were termed Adjacent Cases. For not only is it no ultimate, but not even a

causal law. Changes do indeed take place in human affairs, but every one

of those changes depends on determinate causes; the “progressiveness of

the species” is not a cause, but a summary expression for the general

result of all the causes. So soon as, by a quite different sort of

induction, it shall be ascertained what causes have produced these

successive changes, from the beginning of history, in so far as they have

really taken place, and by what causes of a contrary tendency they have

been occasionally checked or entirely counteracted, we may then be

prepared to predict the future with reasonable foresight; we may be in

possession of the real _law_ of the future; and may be able to declare on

what circumstances the continuance of the same onward movement will

eventually depend. But this it is the error of many of the more advanced

thinkers, in the present age, to overlook; and to imagine that the

empirical law collected from a mere comparison of the condition of our

species at different past times, is a real law, is _the_ law of its

changes, not only past but also to come. The truth is, that the causes on

which the phenomena of the moral world depend, are in every age, and

almost in every country, combined in some different proportion; so that it

is scarcely to be expected that the general result of them all should

conform very closely, in its details at least, to any uniformly

progressive series. And all generalizations which affirm that mankind have

a tendency to grow better or worse, richer or poorer, more cultivated or

more barbarous, that population increases faster than subsistence, or

subsistence than population, that inequality of fortune has a tendency to

increase or to break down, and the like, propositions of considerable

value as empirical laws within certain (but generally rather narrow)

limits, are in reality true or false according to times and circumstances.

What we have said of empirical generalizations from times past to times

still to come, holds equally true of similar generalizations from present

times to times past; when persons whose acquaintance with moral and social

facts is confined to their own age, take the men and the things of that

age for the type of men and things in general, and apply without scruple

to the interpretation of the events of history, the empirical laws which

represent sufficiently for daily guidance the common phenomena of human

nature at that time and in that particular state of society. If examples

are wanted, almost every historical work, until a very recent period,

abounded in them. The same may be said of those who generalize empirically

from the people of their own country to the people of other countries, as

if human beings felt, judged, and acted everywhere in the same manner.

§ 5. In the foregoing instances, the distinction is confounded between

empirical laws, which express merely the customary order of the succession

of effects, and the laws of causation on which the effects depend. There

may, however, be incorrect generalization when this mistake is not

committed; when the investigation takes its proper direction, that of

causes, and the result erroneously obtained purports to be a really causal

law.

The most vulgar form of this fallacy is that which is commonly called

_post hoc, ergo propter hoc_, or, _cum hoc, ergo propter hoc_. As when it

was inferred that England owed her industrial pre-eminence to her

restrictions on commerce; as when the old school of financiers, and some

speculative writers, maintained that the national debt was one of the

causes of national prosperity; as when the excellence of the Church, of

the Houses of Lords and Commons, of the procedure of the law courts, etc.,

were inferred from the mere fact that the country had prospered under

them. In such cases as these, if it can be rendered probable by other

evidence that the supposed causes have some tendency to produce the effect

ascribed to them, the fact of its having been produced, though only in one

instance, is of some value as a verification by specific experience; but

in itself it goes scarcely any way at all toward establishing such a

tendency, since, admitting the effect, a hundred other antecedents could

show an equally strong title of _that_ kind to be considered as the cause.

In these examples we see bad generalization _a posteriori_, or empiricism

properly so called; causation inferred from casual conjunction, without

either due elimination, or any presumption arising from known properties

of the supposed agent. But bad generalization _a priori_ is fully as

common; which is properly called false theory; conclusions drawn, by way

of deduction, from properties of some one agent which is known or supposed

to be present, all other co-existing agents being overlooked. As the

former is the error of sheer ignorance, so the latter is especially that

of semi-instructed minds; and is mainly committed in attempting to explain

complicated phenomena by a simpler theory than their nature admits of. As

when one school of physicians sought for the universal principle of all

disease in “lentor and morbid viscidity of the blood,” and imputing most

bodily derangements to mechanical obstructions, thought to cure them by

mechanical remedies;(257) while another, the chemical school,

“acknowledged no source of disease but the presence of some hostile acid

or alkali, or some deranged condition in the chemical composition of the

fluid or solid parts,” and conceived, therefore, that “all remedies must

act by producing chemical changes in the body.” We find Tournefort busily

engaged in testing every vegetable juice, in order to discover in it some

traces of an acid or alkaline ingredient, which might confer upon it

medicinal activity. The fatal errors into which such an hypothesis was

liable to betray the practitioner, received an awful illustration in the

history of the memorable fever that raged at Leyden in the year 1699, and

which consigned two-thirds of the population of that city to an untimely

grave; an event which in a great measure depended upon the Professor

Sylvius de la Boe, who having just embraced the chemical doctrines of Van

Helmont, assigned the origin of the distemper to a prevailing acid, and

declared that its cure could alone [only] be effected by the copious

administration of absorbent and testaceous medicines.(258)

These aberrations in medical theory have their exact parallels in

politics. All the doctrines which ascribe absolute goodness to particular

forms of government, particular social arrangements, and even to

particular modes of education, without reference to the state of

civilization and the various distinguishing characters of the society for

which they are intended, are open to the same objection—that of assuming

one class of influencing circumstances to be the paramount rulers of

phenomena which depend in an equal or greater degree on many others. But

on these considerations it is the less necessary that we should now dwell,

as they will occupy our attention more largely in the concluding Book.

§ 6. The last of the modes of erroneous generalization to which I shall

advert, is that to which we may give the name of False Analogies. This

Fallacy stands distinguished from those already treated of by the

peculiarity that it does not even simulate a complete and conclusive

induction, but consists in the misapplication of an argument which is at

best only admissible as an inconclusive presumption, where real proof is

unattainable.

An argument from analogy, is an inference that what is true in a certain

case is true in a case known to be somewhat similar, but not known to be

exactly parallel, that is, to be similar in all the material

circumstances. An object has the property B: another object is not known

to have that property, but resembles the first in a property A, not known

to be connected with B; and the conclusion to which the analogy points, is

that this object has the property B also. As, for example, that the

planets are inhabited, because the earth is so. The planets resemble the

earth in describing elliptical orbits round the sun, in being attracted by

it and by one another, in being nearly spherical, revolving on their axes,

etc.; and, as we have now reason to believe from the revelations of the

spectroscope, are composed, in great part at least, of similar materials;

but it is not known that any of these properties, or all of them together,

are the conditions on which the possession of inhabitants is dependent, or

are marks of those conditions. Nevertheless, so long as we do not know

what the conditions are, they _may_ be connected by some law of nature

with those common properties; and to the extent of that possibility the

planets are more likely to be inhabited than if they did not resemble the

earth at all. This non-assignable and generally small increase of

probability, beyond what would otherwise exist, is all the evidence which

a conclusion can derive from analogy. For if we have the slightest reason

to suppose any real connection between the two properties A and B, the

argument is no longer one of analogy. If it had been ascertained (I

purposely put an absurd supposition) that there was a connection by

causation between the fact of revolving on an axis and the existence of

animated beings, or if there were any reasonable ground for even

suspecting such a connection, a probability would arise of the existence

of inhabitants in the planets, which might be of any degree of strength,

up to a complete induction; but we should then infer the fact from the

ascertained or presumed law of causation, and not from the analogy of the

earth.

The name analogy, however, is sometimes employed by extension to denote

those arguments of an inductive character but not amounting to a real

induction, which are employed to strengthen the argument drawn from a

simple resemblance. Though A, the property common to the two cases, can

not be shown to be the cause or effect of B, the analogical reasoner will

endeavor to show that there is some less close degree of connection

between them; that A is one of a set of conditions from which, when all

united, B would result; or is an occasional effect of some cause which has

been known also to produce B; and the like. Any of which things, if shown,

would render the existence of B by so much more probable, than if there

had not been even that amount of known connection between B and A.

Now an error or fallacy of analogy may occur in two ways. Sometimes it

consists in employing an argument of either of the above kinds with

correctness indeed, but overrating its probative force. This very common

aberration is sometimes supposed to be particularly incident to persons

distinguished for their imagination; but in reality it is the

characteristic intellectual vice of those whose imaginations are barren,

either from want of exercise, natural defect, or the narrowness of their

range of ideas. To such minds objects present themselves clothed in but

few properties; and as, therefore, few analogies between one object and

another occur to them, they almost invariably overrate the degree of

importance of those few: while one whose fancy takes a wider range,

perceives and remembers so many analogies tending to conflicting

conclusions, that he is much less likely to lay undue stress on any of

them. We always find that those are the greatest slaves to metaphorical

language who have but one set of metaphors.

But this is only one of the modes of error in the employment of arguments

of analogy. There is another, more properly deserving the name of fallacy;

namely, when resemblance in one point is inferred from resemblance in

another point, though there is not only no evidence to connect the two

circumstances by way of causation, but the evidence tends positively to

disconnect them. This is properly the Fallacy of False Analogies.

As a first instance, we may cite that favorite argument in defense of

absolute power, drawn from the analogy of paternal government in a family,

which government, however much in need of control, is not and can not be

controlled by the children themselves, while they remain children.

Paternal government, says the argument, works well; therefore, despotic

government in a state will work well. I waive, as not pertinent in this

place, all that could be said in qualification of the alleged excellence

of paternal government. However this might be, the argument from the

family to the state would not the less proceed on a false analogy;

implying that the beneficial working of parental government depends, in

the family, on the only point which it has in common with political

despotism, namely, irresponsibility. Whereas it depends, when real, not on

that but on two other circumstances of the case, the affection of the

parent for the children, and the superiority of the parent in wisdom and

experience; neither of which properties can be reckoned on, or are at all

likely to exist, between a political despot and his subjects; and when

either of these circumstances fails even in the family, and the influence

of the irresponsibility is allowed to work uncorrected, the result is any

thing but good government. This, therefore, is a false analogy.

Another example is the not uncommon _dictum_ that bodies politic have

youth, maturity, old age, and death, like bodies natural; that after a

certain duration of prosperity, they tend spontaneously to decay. This

also is a false analogy, because the decay of the vital powers in an

animated body can be distinctly traced to the natural progress of those

very changes of structure which, in their earlier stages, constitutes its

growth to maturity; while in the body politic the progress of those

changes can not, generally speaking, have any effect but the still further

continuance of growth: it is the stoppage of that progress, and the

commencement of retrogression, that alone would constitute decay. Bodies

politic die, but it is of disease, or violent death; they have no old age.

The following sentence from Hooker’s _Ecclesiastical Polity_ is an

instance of a false analogy from physical bodies to what are called bodies

politic. “As there could be in natural bodies no motion of any thing

unless there were some which moveth all things, and continueth immovable;

even so in politic societies there must be some unpunishable, or else no

man shall suffer punishment.” There is a double fallacy here, for not only

the analogy, but the premise from which it is drawn, is untenable. The

notion that there must be something immovable which moves all other

things, is the old scholastic error of a _primum mobile_.

The following instance I quote from Archbishop Whately’s _Rhetoric_: “It

would be admitted that a great and permanent diminution in the quantity of

some useful commodity, such as corn, or coal, or iron, throughout the

world, would be a serious and lasting loss; and again, that if the fields

and coal-mines yielded regularly double quantities, with the same labor,

we should be so much the richer; hence it might be inferred, that if the

quantity of gold and silver in the world were diminished one-half, or were

doubled, like results would follow; the utility of these metals, for the

purposes of coin, being very great. Now there are many points of

resemblance and many of difference, between the precious metals on the one

hand, and corn, coal, etc., on the other; but the important circumstance

to the supposed argument is, that the _utility_ of gold and silver (as

coin, which is far the chief) _depends on their value_, which is regulated

by their scarcity; or rather, to speak strictly, by the difficulty of

obtaining them; whereas, if corn and coal were ten times as abundant

(_i.e._, more easily obtained), a bushel of either would still be as

useful as now. But if it were twice as easy to procure gold as it is, a

sovereign would be twice as large; if only half as easy, it would be of

the size of a half-sovereign, and this (besides the trifling circumstance

of the cheapness or dearness of gold ornaments) would be all the

difference. The analogy, therefore, fails in the point essential to the

argument.”

The same author notices, after Bishop Copleston, the case of False Analogy

which consists in inferring from the similarity in many respects between

the metropolis of a country and the heart of the animal body, that the

increased size of the metropolis is a disease.

Some of the false analogies on which systems of physics were confidently

grounded in the time of the Greek philosophers, are such as we now call

fanciful, not that the resemblances are not often real, but that it is

long since any one has been inclined to draw from them the inferences

which were then drawn. Such, for instance, are the curious speculations of

the Pythagoreans on the subject of numbers. Finding that the distances of

the planets bore, or seemed to bear, to one another a proportion not

varying much from that of the divisions of the monochord, they inferred

from it the existence of an inaudible music, that of the spheres; as if

the music of a harp had depended solely on the numerical proportions, and

not on the material, nor even on the existence of any material, any

strings at all. It has been similarly imagined that certain combinations

of numbers, which were found to prevail in some natural phenomena, must

run through the whole of nature: as that there must be four elements,

because there are four possible combinations of hot and cold, wet and dry;

that there must be seven planets, because there were seven metals, and

even because there were seven days of the week. Kepler himself thought

that there could be only six planets, because there were only five regular

solids. With these we may class the reasonings, so common in the

speculations of the ancients, founded on a supposed _perfection_ in

nature; meaning by nature the customary order of events as they take place

of themselves without human interference. This also is a rude guess at an

analogy supposed to pervade all phenomena, however dissimilar. Since what

was thought to be perfection appeared to obtain in some phenomena, it was

inferred (in opposition to the plainest evidence) to obtain in all. “We

always suppose that which is better to take place in nature, if it be

possible,” says Aristotle; and the vaguest and most heterogeneous

qualities being confounded together under the notion of being _better_,

there was no limit to the wildness of the inferences. Thus, because the

heavenly bodies were “perfect,” they must move in circles and uniformly.

For “they” (the Pythagoreans) “would not allow,” says Geminus,(259) “of

any such disorder among divine and eternal things, as that they should

sometimes move quicker and sometimes slower, and sometimes stand still;

for no one would tolerate such anomaly in the movements even of a man, who

was decent and orderly. The occasions of life, however, are often reasons

for men going quicker or slower; but in the incorruptible nature of the

stars, it is not possible that any cause can be alleged of quickness or

slowness.” It is seeking an argument of analogy very far, to suppose that

the stars must observe the rules of decorum in gait and carriage

prescribed for themselves by the long-bearded philosophers satirized by

Lucian.

As late as the Copernican controversy it was urged as an argument in favor

of the true theory of the solar system, that it placed the fire, the

noblest element, in the centre of the universe. This was a remnant of the

notion that the order of nature must be perfect, and that perfection

consisted in conformity to rules of precedency in dignity, either real or

conventional. Again, reverting to numbers: certain numbers were _perfect_,

therefore those numbers must obtain in the great phenomena of nature. Six

was a perfect number, that is, equal to the sum of all its factors; an

additional reason why there must be exactly six planets. The Pythagoreans,

on the other hand, attributed perfection to the number ten; but agreed in

thinking that the perfect number must be somehow realized in the heavens;

and knowing only of nine heavenly bodies, to make up the enumeration, they

asserted “that there was an _antichthon_, or counter-earth, on the other

side of the sun, invisible to us.”(260) Even Huygens was persuaded that

when the number of the heavenly bodies had reached twelve, it could not

admit of any further increase. Creative power could not go beyond that

sacred number.

Some curious instances of false analogy are to be found in the arguments

of the Stoics to prove the equality of all crimes, and the equal

wretchedness of all who had not realized their idea of perfect virtue.

Cicero, toward the end of his Fourth Book, _De Finibus_, states some of

these as follows: “Ut, inquit, in fidibus plurimis, si nulla earum ita

contenta numeris sit, ut concentum servare possit, omnes æque incontentæ

sunt; sic peccata, quia discrepant, æque discrepant; paria sunt igitur.”

To which Cicero himself aptly answers, “æque contingit omnibus fidibus, ut

incontentæ sint; illud non continuo, ut æque incontentæ.” The Stoic

resumes: “Ut enim, inquit, gubernator æque peccat, si palearum navem

evertit, et si auri; item æque peccat qui parentem, et qui servum, injuriâ

verberat;” assuming, that because the magnitude of the interest at stake

makes no difference in the mere defect of skill, it can make none in the

moral defect: a false analogy. Again, “Quis ignorat, si plures ex alto

emergere velint, propius fore eos quidem ad respirandum, qui ad summam jam

aquam appropinquant, sed nihilo magis respirare posse, quam eos, qui sunt

in profundo? Nihil ergo adjuvat procedere, et progredi in virtute,

quominus miserrimus sit, antequam ad eam pervenerit, quoniam in aquâ nihil

adjuvat: et quoniam catuli, qui jam despecturi sunt, cæci æque, et ii qui

modo nati; Platonem quoque necesse est, quoniam nondum videbat sapientiam,

æque cæcum animo, ac Phalarim fuisse.” Cicero, in his own person, combats

these false analogies by other analogies tending to an opposite

conclusion. “Ista similia non sunt, Cato.... Illa sunt similia; hebes

acies est cuipiam oculorum: corpore alius languescit: hi curatione

adhibitâ levantur in dies: alter valet plus quotidie: alter videt. Hi

similes sunt omnibus, qui virtuti student; levantur vitiis, levantur

erroribus.”

§ 7. In these and all other arguments drawn from remote analogies, and

from metaphors, which are cases of analogy, it is apparent (especially

when we consider the extreme facility of raising up contrary analogies and

conflicting metaphors) that, so far from the metaphor or analogy proving

any thing, the applicability of the metaphor is the very thing to be made

out. It has to be shown that in the two cases asserted to be analogous,

the same law is really operating; that between the known resemblance and

the inferred one there is some connection by means of causation. Cicero

and Cato might have bandied opposite analogies forever; it rested with

each of them to prove by just induction, or at least to render probable,

that the case resembled the one set of analogous cases and not the other,

in the circumstances on which the disputed question really hinged.

Metaphors, for the most part, therefore, assume the proposition which they

are brought to prove: their use is, to aid the apprehension of it; to make

clearly and vividly comprehended what it is that the person who employs

the metaphor is proposing to make out; and sometimes also, by what media

he proposes to do so. For an apt metaphor, though it can not prove, often

suggests the proof.

For instance, when D’Alembert (I believe) remarked that in certain

governments only two creatures find their way to the highest places, the

eagle and the serpent, the metaphor not only conveys with great vividness

the assertion intended, but contributes toward substantiating it, by

suggesting, in a lively manner, the means by which the two opposite

characters thus typified effect their rise. When it is said that a certain

person misunderstands another because the lesser of two objects can not

comprehend the greater, the application of what is true in the literal

sense of the word _comprehend_, to its metaphorical sense, points to the

fact which is the ground and justification of the assertion, viz., that

one mind can not thoroughly understand another unless it can contain it in

itself, that is, unless it possesses all that is contained in the other.

When it is urged as an argument for education, that if the soil is left

uncultivated, weeds will spring up, the metaphor, though no proof, but a

statement of the thing to be proved, states it in terms which, by

suggesting a parallel case, put the mind upon the track of the real proof.

For, the reason why weeds grow in an uncultivated soil, is that the seeds

of worthless products exist everywhere, and can germinate and grow in

almost all circumstances, while the reverse is the case with those which

are valuable; and this being equally true of mental products, this mode of

conveying an argument, independently of its rhetorical advantages, has a

logical value; since it not only suggests the grounds of the conclusion,

but points to another case in which those grounds have been found, or at

least deemed to be, sufficient.

On the other hand, when Bacon, who is equally conspicuous in the use and

abuse of figurative illustration, says that the stream of time has brought

down to us only the least valuable part of the writings of the ancients,

as a river carries froth and straws floating on its surface, while more

weighty objects sink to the bottom; this, even if the assertion

illustrated by it were true, would be no good illustration, there being no

parity of cause. The levity by which substances float on a stream, and the

levity which is synonymous with worthlessness, have nothing in common

except the name; and (to show how little value there is in the metaphor)

we need only change the word into _buoyancy_, to turn the semblance of

argument involved in Bacon’s illustration against himself.

A metaphor, then, is not to be considered as an argument, but as an

assertion that an argument exists; that a parity subsists between the case

from which the metaphor is drawn and that to which it is applied. This

parity may exist though the two cases be apparently very remote from one

another; the only resemblance existing between them may be a resemblance

of relations, an analogy in Ferguson’s and Archbishop Whately’s sense: as

in the preceding instance, in which an illustration from agriculture was

applied to mental cultivation.

§ 8. To terminate the subject of Fallacies of Generalization, it remains

to be said, that the most fertile source of them is bad classification:

bringing together in one group, and under one name, things which have no

common properties, or none but such as are too unimportant to allow

general propositions of any considerable value to be made respecting the

class. The misleading effect is greatest, when a word which in common use

expresses some definite fact, is extended by slight links of connection to

cases in which that fact does not exist, but some other or others, only

slightly resembling it. Thus Bacon,(261) in speaking of the _Idola_ or

Fallacies arising from notions _temere et inæqualiter à rebus abstractæ_,

exemplifies them by the notion of Humidum or Wet, so familiar in the

physics of antiquity and of the Middle Ages. “Invenietur verbum istud,

Humidum, nihil aliud quam nota confusa diversarum actionum, quæ nullam

constantiam aut reductionem patiuntur. Significat enim, et quod circa

aliud corpus facile se circumfundit; et quod in se est indeterminabile,

nec consistere potest; et quod facile cedit undique; et quod facile se

dividit et dispergit; et quod facile se unit et colligit; et quod facile

fluit, et in motu ponitur; et quod alteri corpori facile adhæret, idque

madefacit; et quod facile reducitur in liquidum, sive colliquatur, cum

antea consisteret. Itaque quum ad hujus nominis prædicationem et

impositionem ventum sit; si alia accipias, flamma humida est; si alia

accipias, aer humidus non est; si alia, pulvis minutus humidus est; si

alia, vitrum humidum est: ut facile appareat, istam notionem ex aquâ

tantum, et communibus et vulgaribus liquoribus, absque ullâ debitâ

verificatione, temere abstractam esse.”

Bacon himself is not exempt from a similar accusation when inquiring into

the nature of heat: where he occasionally proceeds like one who, seeking

for the cause of hardness, after examining that quality in iron, flint,

and diamond, should expect to find that it is something which can be

traced also in hard water, a hard knot, and a hard heart.

The word κίνησις in the Greek philosophy, and the words Generation and

Corruption, both then and long afterward, denoted such a multitude of

heterogeneous phenomena, that any attempt at philosophizing in which those

words were used was almost as necessarily abortive as if the word _hard_

had been taken to denote a class including all the things mentioned above.

Κίνησις, for instance, which properly signified motion, was taken to

denote not only all motion but even all change: ἀλλοίωσις being recognized

as one of the modes of κίνησις. The effect was, to connect with every form

of ἀλλοίωσις or change, ideas drawn from motion in the proper and literal

sense, and which had no real connection with any other kind of κίνησις

than that. Aristotle and Plato labored under a continual embarrassment

from this misuse of terms. But if we proceed further in this direction we

shall encroach upon the Fallacy of Ambiguity, which belongs to a different

class, the last in order of our classification, Fallacies of Confusion.

Chapter VI.

Fallacies Of Ratiocination.

§ 1. We have now, in our progress through the classes of Fallacies,

arrived at those to which, in the common books of logic, the appellation

is in general exclusively appropriated; those which have their seat in the

ratiocinative or deductive part of the investigation of truth. Of these

fallacies it is the less necessary for us to insist at any length, as they

have been most satisfactorily treated in a work familiar to almost all, in

this country at least, who feel any interest in these speculations,

Archbishop Whately’s _Logic_. Against the more obvious forms of this class

of fallacies, the rules of the syllogism are a complete protection. Not

(as we have so often said) that ratiocination can not be good unless it be

in the form of a syllogism; but that, by showing it in that form, we are

sure to discover if it be bad, or at least if it contain any fallacy of

this class.

§ 2. Among Fallacies of Ratiocination, we ought perhaps to include the

errors committed in processes which have the appearance only, not the

reality, of an inference from premises; the fallacies connected with the

conversion and æquipollency of propositions. I believe errors of this

description to be far more frequently committed than is generally

supposed, or than their extreme obviousness might seem to admit of. For

example, the simple conversion of a universal affirmative proposition, All

A are B, therefore all B are A, I take to be a very common form of error:

though committed, like many other fallacies, oftener in the silence of

thought than in express words, for it can scarcely be clearly enunciated

without being detected. And so with another form of fallacy, not

substantially different from the preceding: the erroneous conversion of an

hypothetical proposition. The proper converse of an hypothetical

proposition is this: If the consequent be false, the antecedent is false;

but this, If the consequent be true, the antecedent is true, by no means

holds good, but is an error corresponding to the simple conversion of a

universal affirmative. Yet hardly any thing is more common than for

people, in their private thoughts, to draw this inference. As when the

conclusion is accepted, which it so often is, for proof of the premises.

That the premises can not be true if the conclusion is false, is the

unexceptionable foundation of the legitimate mode of reasoning called

_reductio ad absurdum_. But people continually think and express

themselves, as if they also believed that the premises can not be false if

the conclusion is true. The truth, or supposed truth, of the inferences

which follow from a doctrine, often enables it to find acceptance in spite

of gross absurdities in it. How many philosophical systems which had

scarcely any intrinsic recommendation, have been received by thoughtful

men because they were supposed to lend additional support to religion,

morality, some favorite view of politics, or some other cherished

persuasion: not merely because their wishes were thereby enlisted on its

side, but because its leading to what they deemed sound conclusions

appeared to them a strong presumption in favor of its truth: though the

presumption, when viewed in its true light, amounted only to the absence

of that particular evidence of falsehood, which would have resulted from

its leading by correct inference to something already known to be false.

Again, the very frequent error in conduct, of mistaking reverse of wrong

for right, is the practical form of a logical error with respect to the

Opposition of Propositions. It is committed for want of the habit of

distinguishing the _contrary_ of a proposition from the _contradictory_ of

it, and of attending to the logical canon, that contrary propositions,

though they can not both be true, may both be false. If the error were to

express itself in words, it would run distinctly counter to this canon. It

generally, however, does not so express itself, and to compel it to do so

is the most effectual method of detecting and exposing it.

§ 3. Among Fallacies of Ratiocination are to be ranked, in the first

place, all the cases of vicious syllogism laid down in the books. These

generally resolve themselves into having more than three terms to the

syllogism, either avowedly, or in the covert mode of an undistributed

middle term, or an _illicit process_ of one of the two extremes. It is

not, indeed, very easy fully to convict an argument of falling under any

one of these vicious cases in particular; for the reason already more than

once referred to, that the premises are seldom formally set out: if they

were, the fallacy would impose upon nobody; and while they are not, it is

almost always to a certain degree optional in what manner the suppressed

link shall be filled up. The rules of the syllogism are rules for

compelling a person to be aware of the whole of what he must undertake to

defend if he persists in maintaining his conclusion. He has it almost

always in his power to make his syllogism good by introducing a false

premise; and hence it is scarcely ever possible decidedly to affirm that

any argument involves a bad syllogism: but this detracts nothing from the

value of the syllogistic rules, since it is by them that a reasoner is

compelled distinctly to make his election what premises he is prepared to

maintain. The election made, there is generally so little difficulty in

seeing whether the conclusion follows from the premises set out, that we

might without much logical impropriety have merged this fourth class of

fallacies in the fifth, or Fallacies of Confusion.

§ 4. Perhaps, however, the commonest, and certainly the most dangerous

fallacies of this class, are those which do not lie in a single syllogism,

but slip in between one syllogism and another in a chain of argument, and

are committed by _changing the premises_. A proposition is proved, or an

acknowledged truth laid down, in the first part of an argumentation, and

in the second a further argument is founded not on the same proposition,

but on some other, resembling it sufficiently to be mistaken for it.

Instances of this fallacy will be found in almost all the argumentative

discourses of unprecise thinkers; and we need only here advert to one of

the obscurer forms of it, recognized by the school-men as the fallacy _à

dicto secundum quid ad dictum simpliciter_. This is committed when, in the

premises, a proposition is asserted with a qualification, and the

qualification lost sight of in the conclusion; or oftener, when a

limitation or condition, though not asserted, is necessary to the truth of

the proposition, but is forgotten when that proposition comes to be

employed as a premise. Many of the bad arguments in vogue belong to this

class of error. The premise is some admitted truth, some common maxim, the

reasons or evidence for which have been forgotten, or are not thought of

at the time, but if they had been thought of would have shown the

necessity of so limiting the premise that it would no longer have

supported the conclusion drawn from it.

Of this nature is the fallacy in what is called, by Adam Smith and others,

the Mercantile Theory in Political Economy. That theory sets out from the

common maxim, that whatever brings in money enriches; or that every one is

rich in proportion to the quantity of money he obtains. From this it is

concluded that the value of any branch of trade, or of the trade of the

country altogether, consists in the balance of money it brings in; that

any trade which carries more money out of the country than it draws into

it is a losing trade; that therefore money should be attracted into the

country and kept there, by prohibitions and bounties; and a train of

similar corollaries. All for want of reflecting that if the riches of an

individual are in proportion to the quantity of money he can command, it

is because that is the measure of his power of purchasing money’s worth;

and is therefore subject to the proviso that he is not debarred from

employing his money in such purchases. The premise, therefore, is only

true _secundum quid_; but the theory assumes it to be true absolutely, and

infers that increase of money is increase of riches, even when produced by

means subversive of the condition under which alone money can be riches.

A second instance is, the argument by which it used to be contended,

before the commutation of tithe, that tithes fell on the landlord, and

were a deduction from rent; because the rent of tithe-free land was always

higher than that of land of the same quality, and the same advantages of

situation, subject to tithe. Whether it be true or not that a tithe falls

on rent, a treatise on Logic is not the place to examine; but it is

certain that this is no proof of it. Whether the proposition be true or

false, tithe-free land must, by the necessity of the case, pay a higher

rent. For if tithes do not fall on rent, it must be because they fall on

the consumer; because they raise the price of agricultural produce. But if

the produce be raised in price, the farmer of tithe-free as well as the

farmer of tithed land gets the benefit. To the latter the rise is but a

compensation for the tithe he pays; to the first, who pays none, it is

clear gain, and therefore enables him, and if there be freedom of

competition, forces him, to pay so much more rent to his landlord. The

question remains, to what class of fallacies this belongs. The premise is,

that the owner of tithed land receives less rent than the owner of

tithe-free land; the conclusion is, that therefore he receives less than

he himself would receive if tithe were abolished. But the premise is only

true conditionally; the owner of tithed land receives less than what the

owner of tithe-free land is enabled to receive _when other lands are

tithed_; while the conclusion is applied to a state of circumstances in

which that condition fails, and in which, by consequence, the premise will

not be true. The fallacy, therefore, is _à dicto secundum quid ad dictum

simpliciter_.

A third example is the opposition sometimes made to legitimate

interferences of government in the economical affairs of society, grounded

on a misapplication of the maxim, that an individual is a better judge

than the government of what is for his own pecuniary interest. This

objection was urged to Mr. Wakefield’s principle of colonization; the

concentration of the settlers, by fixing such a price on unoccupied land

as may preserve the most desirable proportion between the quantity of land

in culture and the laboring population. Against this it was argued, that

if individuals found it for their advantage to occupy extensive tracts of

land, they, being better judges of their own interest than the legislature

(which can only proceed on general rules), ought not to be restrained from

doing so. But in this argument it was forgotten that the fact of a

person’s taking a large tract of land is evidence only that it is his

interest to take as much as other people, but not that it might not be for

his interest to content himself with less, if he could be assured that

other people would do so too; an assurance which nothing but a government

regulation can give. If all other people took much, and he only a little,

he would reap none of the advantages derived from the concentration of the

population and the consequent possibility of procuring labor for hire, but

would have placed himself, without equivalent, in a situation of voluntary

inferiority. The proposition, therefore, that the quantity of land which

people will take when left to themselves is that which is most for their

interest to take, is true only _secundum quid_: it is only their interest

while they have no guarantee for the conduct of one another. But the

arrangement disregards the limitation, and takes the proposition for true

_simpliciter_.

One of the conditions oftenest dropped, when what would otherwise be a

true proposition is employed as a premise for proving others, is the

condition of _time_. It is a principle of political economy that prices,

profits, wages, etc., “always find their level;” but this is often

interpreted as if it meant that they are always, or generally, _at_ their

level, while the truth is, as Coleridge epigrammatically expresses it,

that they are always _finding_ their level, “which might be taken as a

paraphrase or ironical definition of a storm.”

Under the same head of fallacy (_à dicto secundum quid ad dictum

simpliciter_) might be placed all the errors which are vulgarly called

misapplications of abstract truths; that is, where a principle, true (as

the common expression is) _in the abstract_, that is, all modifying causes

being supposed absent, is reasoned on as if it were true absolutely, and

no modifying circumstance could ever by possibility exist. This very

common form of error it is not requisite that we should exemplify here, as

it will be particularly treated of hereafter in its application to the

subjects on which it is most frequent and most fatal, those of politics

and society.(262)

Chapter VII.

Fallacies Of Confusion.

§ 1. Under this fifth and last class it is convenient to arrange all those

fallacies in which the source of error is not so much a false estimate of

the probative force of known evidence, as an indistinct, indefinite, and

fluctuating conception of what the evidence is.

At the head of these stands that multitudinous body of fallacious

reasonings in which the source of error is the ambiguity of terms: when

something which is true if a word be used in a particular sense, is

reasoned on as if it were true in another sense. In such a case there is

not a mal-estimation of evidence, because there is not properly any

evidence to the point at all; there is evidence, but to a different point,

which from a confused apprehension of the meaning of the terms used, is

supposed to be the same. This error will naturally be oftener committed in

our ratiocinations than in our direct inductions, because in the former we

are deciphering our own or other people’s notes, while in the latter we

have the things themselves present, either to the senses or to the memory.

Except, indeed, when the induction is not from individual cases to a

generality, but from generalities to a still higher generalization; in

that case the fallacy of ambiguity may affect the inductive process as

well as the ratiocinative. It occurs in ratiocination in two ways: when

the middle term is ambiguous, or when one of the terms of the syllogism is

taken in one sense in the premises, and in another sense in the

conclusion.

Some good exemplifications of this fallacy are given by Archbishop

Whately. “One case,” says he, “which may be regarded as coming under the

head of Ambiguous Middle, is (what I believe logical writers mean by

‘_Fallacia Figuræ Dictionis_’) the fallacy built on the grammatical

structure of language, from men’s usually taking for granted that

_paronymous_ (or _conjugate_) words, _i.e._, those belonging to each

other, as the substantive, adjective, verb, etc., of the same root, have a

precisely corresponding meaning; which is by no means universally the

case. Such a fallacy could not indeed be even exhibited in strict logical

form, which would preclude even the attempt at it, since it has two middle

terms in sound as well as sense. But nothing is more common in practice

than to vary continually the terms employed, with a view to grammatical

convenience; nor is there any thing unfair in such a practice, as long as

the _meaning_ is preserved unaltered; _e.g._, ‘murder should be punished

with death; this man is a murderer, therefore he deserves to die,’ etc.

Here we proceed on the assumption (in this case just) that to commit

murder, and to be a murderer—to deserve death, and to be one who ought to

die, are, respectively, equivalent expressions; and it would frequently

prove a heavy inconvenience to be debarred this kind of liberty; but the

abuse of it gives rise to the Fallacy in question; _e.g._, _projectors_

are unfit to be trusted; this man has formed a _project_, therefore he is

unfit to be trusted: here the sophist proceeds on the hypothesis that he

who forms a _project_ must be a _projector_: whereas the bad sense that

commonly attaches to the latter word, is not at all implied in the former.

This fallacy may often be considered as lying not in the Middle, but in

one of the terms of the Conclusion; so that the conclusion drawn shall not

be, in reality, at all warranted by the premises, though it will appear to

be so, by means of the grammatical affinity of the words; _e.g._, to be

acquainted with the guilty is a _presumption_ of guilt; this man is so

acquainted, therefore we may _presume_ that he is guilty: this argument

proceeds on the supposition of an exact correspondence between _presume_

and _presumption_, which, however, does not really exist; for

‘presumption’ is commonly used to express a kind of _slight suspicion_;

whereas, ‘to presume’ amounts to actual belief. There are innumerable

instances of a non-correspondence in paronymous words, similar to that

above instanced; as between _art_ and _artful_, _design_ and _designing_,

_faith_ and _faithful_, etc.; and the more slight the variation of the

meaning, the more likely is the fallacy to be successful; for when the

words have become so widely removed in sense as ‘pity’ and ‘pitiful,’

every one would perceive such a fallacy, nor would it be employed but in

jest.(263)

“The present Fallacy is nearly allied to, or rather, perhaps, may be

regarded as a branch of, that founded on _etymology_—viz., when a term is

used, at one time in its customary, and at another in its etymological

sense. Perhaps no example of this can be found that is more extensively

and mischievously employed than in the case of the word _representative_:

assuming that its right meaning must correspond exactly with the strict

and original sense of the verb ‘represent,’ the sophist persuades the

multitude that a member of the House of Commons is bound to be guided in

all points by the opinion of his constituents; and, in short, to be merely

their _spokesman_; whereas law and custom, which in this case may be

considered as fixing the meaning of the term, require no such thing, but

enjoin the representative to act according to the best of his _own_

judgment, and on his own responsibility.”

The following are instances of great practical importance, in which

arguments are habitually founded on a verbal ambiguity.

The mercantile public are frequently led into this fallacy by the phrase

“scarcity of money.” In the language of commerce, “money” has two

meanings: _currency_, or the circulating medium; and _capital seeking

investment_, especially investment on loan. In this last sense the word is

used when the “money market” is spoken of, and when the “value of money”

is said to be high or low, the rate of interest being meant. The

consequence of this ambiguity is, that as soon as scarcity of money in the

latter of these senses begins to be felt—as soon as there is difficulty of

obtaining loans, and the rate of interest is high—it is concluded that

this must arise from causes acting upon the quantity of money in the other

and more popular sense; that the circulating medium must have diminished

in quantity, or ought to be increased. I am aware that, independently of

the double meaning of the term, there are in the facts themselves some

peculiarities, giving an apparent support to this error; but the ambiguity

of the language stands on the very threshold of the subject, and

intercepts all attempts to throw light upon it.

Another ambiguous expression which continually meets us in the political

controversies of the present time, especially in those which relate to

organic changes, is the phrase “influence of property”—which is sometimes

used for the influence of respect for superior intelligence or gratitude

for the kind offices which persons of large property have it so much in

their power to bestow; at other times for the influence of fear; fear of

the worst sort of power, which large property also gives to its possessor,

the power of doing mischief to dependents. To confound these two, is the

standing fallacy of ambiguity brought against those who seek to purify the

electoral system from corruption and intimidation. Persuasive influence,

acting through the conscience of the voter, and carrying his heart and

mind with it, is beneficial—therefore (it is pretended) coercive

influence, which compels him to forget that he is a moral agent, or to act

in opposition to his moral convictions, ought not to be placed under

restraint.

Another word which is often turned into an instrument of the fallacy of

ambiguity, is Theory. In its most proper acceptation, theory means the

completed result of philosophical induction from experience. In that

sense, there are erroneous as well as true theories, for induction may be

incorrectly performed, but theory of some sort is the necessary result of

knowing any thing of a subject, and having put one’s knowledge into the

form of general propositions for the guidance of practice. In this, the

proper sense of the word, Theory is the explanation of practice. In

another and a more vulgar sense, theory means any mere fiction of the

imagination, endeavoring to conceive how a thing may possibly have been

produced, instead of examining how it was produced. In this sense only are

theory and theorists unsafe guides; but because of this, ridicule or

discredit is attempted to be attached to theory in its proper sense, that

is, to legitimate generalization, the end and aim of all philosophy; and a

conclusion is represented as worthless, just because that has been done

which, if done correctly, constitutes the highest worth that a principle

for the guidance of practice can possess, namely, to comprehend in a few

words the real law on which a phenomenon depends, or some property or

relation which is universally true of it.

“The Church” is sometimes understood to mean the clergy alone, sometimes

the whole body of believers, or at least of communicants. The declamations

respecting the inviolability of church property are indebted for the

greater part of their apparent force to this ambiguity. The clergy, being

called the church, are supposed to be the real owners of what is called

church property; whereas they are in truth only the managing members of a

much larger body of proprietors, and enjoy on their own part a mere

usufruct, not extending beyond a life interest.

The following is a Stoical argument taken from Cicero, _De Finibus_, book

the third: “Quod est bonum, omne laudabile est. Quod autem laudabile est,

omne honestum est. Bonum igitur quod est, honestum est.” Here the

ambiguous word is _laudabile_, which in the minor premise means any thing

which mankind are accustomed, on good grounds, to admire or value; as

beauty, for instance, or good fortune: but in the major, it denotes

exclusively moral qualities. In much the same manner the Stoics endeavored

logically to justify as philosophical truths, their figurative and

rhetorical expressions of ethical sentiment: as that the virtuous man is

alone free, alone beautiful, alone a king, etc. Whoever has virtue has

Good (because it has been previously determined not to call any thing else

good); but, again, Good necessarily includes freedom, beauty, and even

kingship, all these being good things; therefore whoever has virtue has

all these.

The following is an argument of Descartes to prove, in his _a priori_

manner, the being of a God. The conception, says he, of an infinite Being

proves the real existence of such a being. For if there is not really any

such being, _I_ must have made the conception; but if I could make it, I

can also unmake it; which evidently is not true; therefore there must be,

externally to myself, an archetype, from which the conception was derived.

In this argument (which, it may be observed, would equally prove the real

existence of ghosts and of witches) the ambiguity is in the pronoun _I_,

by which, in one place, is to be understood my _will_, in another the

_laws of my nature_. If the conception, existing as it does in my mind,

had no original without, the conclusion would unquestionably follow that

_I_ made it; that is, the laws of my nature must have somehow evolved it:

but that my _will_ made it, would not follow. Now when Descartes afterward

adds that I can not unmake the conception, he means that I can not get rid

of it by an act of my will: which is true, but is not the proposition

required. I can as much unmake this conception as I can any other: no

conception which I have once had, can I ever dismiss by mere volition; but

what some of the laws of my nature have produced, other laws, or those

same laws in other circumstances, may, and often do, subsequently efface.