MISCELLANEOUS EXAMPLES OF THE EXPLANATION OF LAWS OF NATURE.
§ 1. The most striking example which the history of science presents, of
the explanation of laws of causation and other uniformities of sequence
among special phenomena, by resolving them into laws of greater
simplicity and generality, is the great Newtonian generalization:
respecting which typical instance so much having already been said, it
is sufficient to call attention to the great number and variety of the
special observed uniformities which are in this case accounted for,
either as particular cases or as consequences of one very simple law of
universal nature. The simple fact of a tendency of every particle of
matter towards every other particle, varying inversely as the square of
the distance, explains the fall of bodies to the earth, the revolutions
of the planets and satellites, the motions (so far as known) of comets,
and all the various regularities which have been observed in these
special phenomena; such as the elliptical orbits, and the variations
from exact ellipses; the relation between the solar distances of the
planets and the duration of their revolutions; the precession of the
equinoxes; the tides, and a vast number of minor astronomical truths.
Mention has also been made in the preceding chapter of the explanation
of the phenomena of magnetism from laws of electricity; the special laws
of magnetic agency having been affiliated by deduction to observed laws
of electric action, in which they have ever since been considered to be
included as special cases. An example not so complete in itself, but
even more fertile in consequences, having been the starting point of the
really scientific study of physiology, is the affiliation, commenced by
Bichat, and carried on by subsequent biologists, of the properties of
the bodily organs, to the elementary properties of the tissues into
which they are anatomically decomposed.
Another striking instance is afforded by Dalton's generalization,
commonly known as the atomic theory. It had been known from the very
commencement of accurate chemical observation, that any two bodies
combine chemically with one another in only a certain number of
proportions; but those proportions were in each case expressed by a
percentage--so many parts (by weight) of each ingredient, in 100 of the
compound; (say 35 and a fraction of one element, 64 and a fraction of
the other): in which mode of statement no relation was perceived between
the proportion in which a given element combines with one substance, and
that in which it combines with others. The great step made by Dalton
consisted in perceiving, that a unit of weight might be established for
each substance, such that by supposing the substance to enter into all
its combinations in the ratio either of that unit, or of some low
multiple of that unit, all the different proportions, previously
expressed by percentages, were found to result. Thus 1 being assumed as
the unit of hydrogen, if 8 were then taken as that of oxygen, the
combination of one unit of hydrogen with one unit of oxygen would
produce the exact proportion of weight between the two substances which
is known to exist in water; the combination of one unit of hydrogen with
two units of oxygen would produce the proportion which exists in the
other compound of the same two elements, called peroxide of hydrogen;
and the combinations of hydrogen and of oxygen with all other
substances, would correspond with the supposition that those elements
enter into combination by single units, or twos, or threes, of the
numbers assigned to them, 1 and 8, and the other substances by ones or
twos or threes of other determinate numbers proper to each. The result
is that a table of the equivalent numbers, or, as they are called,
atomic weights, of all the elementary substances, comprises in itself,
and scientifically explains, all the proportions in which any substance,
elementary or compound, is found capable of entering into chemical
combination with any other substance whatever.
§ 2. Some interesting cases of the explanation of old uniformities by
newly ascertained laws are afforded by the researches of Professor
Graham. That eminent chemist was the first who drew attention to the
distinction which may be made of all substances into two classes, termed
by him crystalloids and colloids; or rather, of all states of matter
into the crystalloid and the colloidal states, for many substances are
capable of existing in either. When in the colloidal state, their
sensible properties are very different from those of the same substance
when crystallized, or when in a state easily susceptible of
crystallization. Colloid substances pass with extreme difficulty and
slowness into the crystalline state, and are extremely inert in all the
ordinary chemical relations. Substances in the colloid state are almost
always, when combined with water, more or less viscous or gelatinous.
The most prominent examples of the state are certain animal and
vegetable substances, particularly gelatine, albumen, starch, the gums,
caramel, tannin, and some others. Among substances not of organic
origin, the most notable instances are hydrated silicic acid, and
hydrated alumina, with other metallic peroxides of the aluminous class.
Now it is found, that while colloidal substances are easily penetrated
by water, and by the solutions of crystalloid substances, they are very
little penetrable by one another: which enabled Professor Graham to
introduce a highly effective process (termed dialysis) for separating
the crystalloid substances contained in any liquid mixture, by passing
them through a thin septum of colloidal matter, which does not suffer
anything colloidal to pass, or suffers it only in very minute quantity.
This property of colloids enabled Mr. Graham to account for a number of
special results of observation, not previously explained.
For instance, "while soluble crystalloids are always highly sapid,
soluble colloids are singularly insipid," as might be expected; for, as
the sentient extremities of the nerves of the palate "are probably
protected by a colloidal membrane," impermeable to other colloids, a
colloid, when tasted, probably never reaches those nerves. Again, "it
has been observed that vegetable gum is not digested in the stomach; the
coats of that organ dialyse the soluble food, absorbing crystalloids,
and rejecting all colloids." One of the mysterious processes
accompanying digestion, the secretion of free muriatic acid by the coats
of the stomach, obtains a probable hypothetical explanation through the
same law. Finally, much light is thrown upon the observed phenomena of
osmose (the passage of fluids outward and inward through animal
membranes) by the fact that the membranes are colloidal. In consequence,
the water and saline solutions contained in the animal body pass easily
and rapidly through the membranes, while the substances directly
applicable to nutrition, which are mostly colloidal, are detained by
them.[47]
The property which salt possesses of preserving animal substances from
putrefaction is resolved by Liebig into two more general laws, the
strong attraction of salt for water, and the necessity of the presence
of water as a condition of putrefaction. The intermediate phenomenon
which is interpolated between the remote cause and the effect, can here
be not merely inferred but seen; for it is a familiar fact, that flesh
upon which salt has been thrown is speedily found swimming in brine.
The second of the two factors (as they may be termed) into which the
preceding law has been resolved, the necessity of water to putrefaction,
itself affords an additional example of the Resolution of Laws. The law
itself is proved by the Method of Difference, since flesh completely
dried and kept in a dry atmosphere does not putrefy; as we see in the
case of dried provisions, and human bodies in very dry climates. A
deductive explanation of this same law results from Liebig's
speculations. The putrefaction of animal and other azotised bodies is a
chemical process, by which they are gradually dissipated in a gaseous
form, chiefly in that of carbonic acid and ammonia; now to convert the
carbon of the animal substance into carbonic acid requires oxygen, and
to convert the azote into ammonia requires hydrogen, which are the
elements of water. The extreme rapidity of the putrefaction of azotised
substances, compared with the gradual decay of non-azotised bodies (such
as wood and the like) by the action of oxygen alone, he explains from
the general law that substances are much more easily decomposed by the
action of two different affinities upon two of their elements, than by
the action of only one.
§ 3. Among the many important properties of the nervous system, which
have either been first discovered or strikingly illustrated by Dr.
Brown-Séquard, I select the reflex influence of the nervous system on
nutrition and secretion. By reflex nervous action is meant, action which
one part of the nervous system exerts over another part, without any
intermediate action on the brain, and consequently without
consciousness; or which, if it does pass through the brain, at least
produces its effects independently of the will. There are many
experiments which prove that irritation of a nerve in one part of the
body may in this manner excite powerful action in another part; for
example, food injected into the stomach through a divided oesophagus,
nevertheless produces secretion of saliva; warm water injected into the
bowels, and various other irritations of the lower intestines, have been
found to excite secretion of the gastric juice, and so forth. The
reality of the power being thus proved, its agency explains a great
variety of apparently anomalous phenomena; of which I select the
following from Dr. Brown-Séquard's _Lectures on the Nervous System_.
The production of tears by irritation of the eye, or of the mucous
membrane of the nose:
The secretions of the eye and nose increased by exposure of other parts
of the body to cold:
Inflammation of the eye, especially when of traumatic origin, very
frequently excites a similar affection in the other eye, which may be
cured by section of the intervening nerve:
Loss of sight sometimes produced by neuralgia; and has been known to be
at once cured by the extirpation (for instance) of a carious tooth:
Even cataract has been produced in a healthy eye by cataract in the
other eye, or by neuralgia, or by a wound of the frontal nerve:
The well-known phenomenon of a sudden stoppage of the heart's action,
and consequent death, produced by irritation of some of the nervous
extremities: _e.g._, by drinking very cold water; or by a blow on the
abdomen, or other sudden excitation of the abdominal sympathetic nerve;
though this nerve may be irritated to any extent without stopping the
heart's action, if a section be made of the communicating nerves:
The extraordinary effects produced on the internal organs by an
extensive burn on the surface of the body; consisting in violent
inflammation of the tissues of the abdomen, chest, or head: which, when
death ensues from this kind of injury, is one of the most frequent
causes of it:
Paralysis and anæsthesia of one part of the body from neuralgia in
another part; and muscular atrophy from neuralgia, even when there is no
paralysis:
Tetanus produced by the lesion of a nerve; Dr. Brown-Séquard thinks it
highly probable that hydrophobia is a phenomenon of a similar nature:
Morbid changes in the nutrition of the brain and spinal cord,
manifesting themselves by epilepsy, chorea, hysteria, and other
diseases, occasioned by lesion of some of the nervous extremities in
remote places, as by worms, calculi, tumours, carious bones, and in some
cases even by very slight irritations of the skin.
§ 4. From the foregoing and similar instances, we may see the
importance, when a law of nature previously unknown has been brought to
light, or when new light has been thrown upon a known law by experiment,
of examining all cases which present the conditions necessary for
bringing that law into action; a process fertile in demonstrations of
special laws previously unsuspected, and explanations of others already
empirically known.
For instance, Faraday discovered by experiment, that voltaic electricity
could be evolved from a natural magnet, provided a conducting body were
set in motion at right angles to the direction of the magnet: and this
he found to hold not only of small magnets, but of that great magnet,
the earth. The law being thus established experimentally, that
electricity is evolved, by a magnet, and a conductor moving at right
angles to the direction of its poles, we may now look out for fresh
instances in which these conditions meet. Wherever a conductor moves or
revolves at right angles to the direction of the earth's magnetic poles,
there we may expect an evolution of electricity. In the northern
regions, where the polar direction is nearly perpendicular to the
horizon, all horizontal motions of conductors will produce electricity;
horizontal wheels, for example, made of metal; likewise all running
streams will evolve a current of electricity, which will circulate round
them; and the air thus charged with electricity may be one of the causes
of the Aurora Borealis. In the equatorial regions, on the contrary,
upright wheels placed parallel to the equator will originate a voltaic
circuit, and waterfalls will naturally become electric.
For a second example; it has been proved, chiefly by the researches of
Professor Graham, that gases have a strong tendency to permeate animal
membranes, and diffuse themselves through the spaces which such
membranes inclose, notwithstanding the presence of other gases in those
spaces. Proceeding from this general law, and reviewing a variety of
cases in which gases lie contiguous to membranes, we are enabled to
demonstrate or to explain the following more special laws: 1st. The
human or animal body, when surrounded with any gas not already contained
within the body, absorbs it rapidly; such, for instance, as the gases of
putrefying matters: which helps to explain malaria. 2nd. The carbonic
acid gas of effervescing drinks, evolved in the stomach, permeates its
membranes, and rapidly spreads through the system. 3rd. Alcohol taken
into the stomach passes into vapour and spreads through the system with
great rapidity; (which, combined with the high combustibility of
alcohol, or in other words its ready combination with oxygen, may
perhaps help to explain the bodily warmth immediately consequent on
drinking spirituous liquors.) 4th. In any state of the body in which
peculiar gases are formed within it, these will rapidly exhale through
all parts of the body; and hence the rapidity with which, in certain
states of disease, the surrounding atmosphere becomes tainted. 5th. The
putrefaction of the interior parts of a carcase will proceed as rapidly
as that of the exterior, from the ready passage outwards of the gaseous
products. 6th. The exchange of oxygen and carbonic acid in the lungs is
not prevented, but rather promoted, by the intervention of the membrane
of the lungs and the coats of the blood-vessels between the blood and
the air. It is necessary, however, that there should be a substance in
the blood with which the oxygen of the air may immediately combine;
otherwise instead of passing into the blood, it would permeate the whole
organism: and it is necessary that the carbonic acid, as it is formed in
the capillaries, should also find a substance in the blood with which it
can combine; otherwise it would leave the body at all points, instead of
being discharged through the lungs.
§ 5. The following is a deduction which confirms, by explaining, the old
but not undisputed empirical generalization, that soda powders weaken
the human system. These powders, consisting of a mixture of tartaric
acid with bicarbonate of soda, from which the carbonic acid is set free,
must pass into the stomach as tartrate of soda. Now, neutral tartrates,
citrates, and acetates of the alkalis are found, in their passage
through the system, to be changed into carbonates; and to convert a
tartrate into a carbonate requires an additional quantity of oxygen, the
abstraction of which must lessen the oxygen destined for assimilation
with the blood, on the quantity of which the vigorous action of the
human system partly depends.
The instances of new theories agreeing with and explaining old
empiricisms, are innumerable. All the just remarks made by experienced
persons on human character and conduct, are so many special laws, which
the general laws of the human mind explain and resolve. The empirical
generalizations on which the operations of the arts have usually been
founded, are continually justified and confirmed on the one hand, or
corrected and improved on the other, by the discovery of the simpler
scientific laws on which the efficacy of those operations depends. The
effects of the rotation of crops, of the various manures, and other
processes of improved agriculture, have been for the first time resolved
in our own day into known laws of chemical and organic action, by Davy,
Liebig, and others. The processes of the medical art are even now mostly
empirical: their efficacy is concluded, in each instance, from a special
and most precarious experimental generalization: but as science advances
in discovering the simple laws of chemistry and physiology, progress is
made in ascertaining the intermediate links in the series of phenomena,
and the more general laws on which they depend; and thus, while the old
processes are either exploded, or their efficacy, in so far as real,
explained, better processes, founded on the knowledge of proximate
causes, are continually suggested and brought into use.[48] Many even of
the truths of geometry were generalizations from experience before they
were deduced from first principles. The quadrature of the cycloid is
said to have been first effected by measurement, or rather by weighing a
cycloidal card, and comparing its weight with that of a piece of similar
card of known dimensions.
§ 6. To the foregoing examples from physical science, let us add another
from mental. The following is one of the simple laws of mind: Ideas of a
pleasurable or painful character form associations more easily and
strongly than other ideas, that is, they become associated after fewer
repetitions, and the association is more durable. This is an
experimental law, grounded on the Method of Difference. By deduction
from this law, many of the more special laws which experience shows to
exist among particular mental phenomena may be demonstrated and
explained:--the ease and rapidity, for instance, with which thoughts
connected with our passions or our more cherished interests are excited,
and the firm hold which the facts relating to them have on our memory;
the vivid recollection we retain of minute circumstances which
accompanied any object or event that deeply interested us, and of the
times and places in which we have been very happy or very miserable; the
horror with which we view the accidental instrument of any occurrence
which shocked us, or the locality where it took place, and the pleasure
we derive from any memorial of past enjoyment; all these effects being
proportional to the sensibility of the individual mind, and to the
consequent intensity of the pain or pleasure from which the association
originated. It has been suggested by the able writer of a biographical
sketch of Dr. Priestley in a monthly periodical,[49] that the same
elementary law of our mental constitution, suitably followed out, would
explain a variety of mental phenomena previously inexplicable, and in
particular some of the fundamental diversities of human character and
genius. Associations being of two sorts, either between synchronous, or
between successive impressions; and the influence of the law which
renders associations stronger in proportion to the pleasurable or
painful character of the impressions, being felt with peculiar force in
the synchronous class of associations; it is remarked by the writer
referred to, that in minds of strong organic sensibility synchronous
associations will be likely to predominate, producing a tendency to
conceive things in pictures and in the concrete, richly clothed in
attributes and circumstances, a mental habit which is commonly called
Imagination, and is one of the peculiarities of the painter and the
poet; while persons of more moderate susceptibility to pleasure and pain
will have a tendency to associate facts chiefly in the order of their
succession, and such persons, if they possess mental superiority, will
addict themselves to history or science rather than to creative art.
This interesting speculation the author of the present work has
endeavoured, on another occasion, to pursue farther, and to examine how
far it will avail towards explaining the peculiarities of the poetical
temperament.[50] It is at least an example which may serve, instead of
many others, to show the extensive scope which exists for deductive
investigation in the important and hitherto so imperfect Science of
Mind.
§ 7. The copiousness with which the discovery and explanation of special
laws of phenomena by deduction from simpler and more general ones has
here been exemplified, was prompted by a desire to characterize clearly,
and place in its due position of importance, the Deductive Method;
which, in the present state of knowledge, is destined henceforth
irrevocably to predominate in the course of scientific investigation. A
revolution is peaceably and progressively effecting itself in
philosophy, the reverse of that to which Bacon has attached his name.
That great man changed the method of the sciences from deductive to
experimental, and it is now rapidly reverting from experimental to
deductive. But the deductions which Bacon abolished were from premises
hastily snatched up, or arbitrarily assumed. The principles were neither
established by legitimate canons of experimental inquiry, nor the
results tested by that indispensable element of a rational Deductive
Method, verification by specific experience. Between the primitive
method of Deduction and that which I have attempted to characterize,
there is all the difference which exists between the Aristotelian
physics and the Newtonian theory of the heavens.
It would, however, be a mistake to expect that those great
generalizations, from which the subordinate truths of the more backward
sciences will probably at some future period be deduced by reasoning (as
the truths of astronomy are deduced from the generalities of the
Newtonian theory), will be found, in all, or even in most cases, among
truths now known and admitted. We may rest assured, that many of the
most general laws of nature are as yet entirely unthought of; and that
many others, destined hereafter to assume the same character, are known,
if at all, only as laws or properties of some limited class of
phenomena; just as electricity, now recognised as one of the most
universal of natural agencies, was once known only as a curious property
which certain substances acquired by friction, of first attracting and
then repelling light bodies. If the theories of heat, cohesion,
crystallization, and chemical action, are destined, as there can be
little doubt that they are, to become deductive, the truths which will
then be regarded as the _principia_ of those sciences would probably, if
now announced, appear quite as novel[51] as the law of gravitation
appeared to the cotemporaries of Newton; possibly even more so, since
Newton's law, after all, was but an extension of the law of weight--that
is, of a generalization familiar from of old, and which already
comprehended a not inconsiderable body of natural phenomena. The general
laws of a similarly commanding character, which we still look forward to
the discovery of, may not always find so much of their foundations
already laid.
These general truths will doubtless make their first appearance in the
character of hypotheses; not proved, nor even admitting of proof, in
the first instance, but assumed as premises for the purpose of deducing
from them the known laws of concrete phenomena. But this, though their
initial, cannot be their final state. To entitle an hypothesis to be
received as one of the truths of nature, and not as a mere technical
help to the human faculties, it must be capable of being tested by the
canons of legitimate induction, and must actually have been submitted to
that test. When this shall have been done, and done successfully,
premises will have been obtained from which all the other propositions
of the science will thenceforth be presented as conclusions, and the
science will, by means of a new and unexpected Induction, be rendered
Deductive.
FOOTNOTES:
[1] Dr. Whewell thinks it improper to apply the term Induction to any
operation not terminating in the establishment of a general truth.
Induction, he says (_Philosophy of Discovery_, p. 245), "is not the same
thing as experience and observation. Induction is experience or
observation _consciously_ looked at in a _general_ form. This
consciousness and generality are necessary parts of that knowledge which
is science." And he objects (p. 241) to the mode in which the word
Induction is employed in this work, as an undue extension of that term
"not only to the cases in which the general induction is consciously
applied to a particular instance, but to the cases in which the
particular instance is dealt with by means of experience in that rude
sense in which experience can be asserted of brutes, and in which of
course we can in no way imagine that the law is possessed or understood
as a general proposition." This use of the term he deems a "confusion of
knowledge with practical tendencies."
I disclaim, as strongly as Dr. Whewell can do, the application of such
terms as induction, inference, or reasoning, to operations performed by
mere instinct, that is, from an animal impulse, without the exertion of
any intelligence. But I perceive no ground for confining the use of
those terms to cases in which the inference is drawn in the forms and
with the precautions required by scientific propriety. To the idea of
Science, an express recognition and distinct apprehension of general
laws as such, is essential: but nine-tenths of the conclusions drawn
from experience in the course of practical life, are drawn without any
such recognition: they are direct inferences from known cases, to a case
supposed to be similar. I have endeavoured to show that this is not only
as legitimate an operation, but substantially the same operation, as
that of ascending from known cases to a general proposition; except that
the latter process has one great security for correctness which the
former does not possess. In Science, the inference must necessarily pass
through the intermediate stage of a general proposition, because Science
wants its conclusions for record, and not for instantaneous use. But the
inferences drawn for the guidance of practical affairs, by persons who
would often be quite incapable of expressing in unexceptionable terms
the corresponding generalizations, may and frequently do exhibit
intellectual powers quite equal to any which have ever been displayed in
Science: and if these inferences are not inductive, what are they? The
limitation imposed on the term by Dr. Whewell seems perfectly arbitrary;
neither justified by any fundamental distinction between what he
includes and what he desires to exclude, nor sanctioned by usage, at
least from the time of Reid and Stewart, the principal legislators (as
far as the English language is concerned) of modern metaphysical
terminology.
[2] Supra, p. 214.
[3] _Novum Organum Renovatum_, pp. 72, 73.
[4] _Novum Organum Renovatum_, p. 32.
[5] _Cours de Philosophie Positive_, vol. ii. p. 202.
[6] Dr. Whewell, in his reply, contests the distinction here drawn, and
maintains, that not only different descriptions, but different
explanations of a phenomenon, may all be true. Of the three theories
respecting the motions of the heavenly bodies, he says (_Philosophy of
Discovery_, p. 231): "Undoubtedly all these explanations may be true and
consistent with each other, and would be so if each had been followed
out so as to show in what manner it could be made consistent with the
facts. And this was, in reality, in a great measure done. The doctrine
that the heavenly bodies were moved by vortices was successfully
modified, so that it came to coincide in its results with the doctrine
of an inverse-quadratic centripetal force.... When this point was
reached, the vortex was merely a machinery, well or ill devised, for
producing such a centripetal force, and therefore did not contradict the
doctrine of a centripetal force. Newton himself does not appear to have
been averse to explaining gravity by impulse. So little is it true that
if one theory be true the other must be false. The attempt to explain
gravity by the impulse of streams of particles flowing through the
universe in all directions, which I have mentioned in the _Philosophy_,
is so far from being inconsistent with the Newtonian theory, that it is
founded entirely upon it. And even with regard to the doctrine, that the
heavenly bodies move by an inherent virtue; if this doctrine had been
maintained in any such way that it was brought to agree with the facts,
the inherent virtue must have had its laws determined; and then it would
have been found that the virtue had a reference to the central body; and
so, the 'inherent virtue' must have coincided in its effect with the
Newtonian force; and then, the two explanations would agree, except so
far as the word 'inherent' was concerned. And if such a part of an
earlier theory as this word _inherent_ indicates, is found to be
untenable, it is of course rejected in the transition to later and more
exact theories, in Inductions of this kind, as well as in what Mr. Mill
calls Descriptions. There is, therefore, still no validity discoverable
in the distinction which Mr. Mill attempts to draw between descriptions
like Kepler's law of elliptical orbits, and other examples of
induction."
If the doctrine of vortices had meant, not that vortices existed, but
only that the planets moved _in the same manner_ as if they had been
whirled by vortices; if the hypothesis had been merely a mode of
representing the facts, not an attempt to account for them; if, in
short, it had been only a Description; it would, no doubt, have been
reconcileable with the Newtonian theory. The vortices, however, were not
a mere aid to conceiving the motions of the planets, but a supposed
physical agent, actively impelling them; a material fact, which might be
true or not true, but could not be both true and not true. According to
Descartes' theory it was true, according to Newton's it was not true.
Dr. Whewell probably means that since the phrases, centripetal and
projectile force, do not declare the nature but only the direction of
the forces, the Newtonian theory does not absolutely contradict any
hypothesis which may be framed respecting the mode of their production.
The Newtonian theory, regarded as a mere _description_ of the planetary
motions, does not; but the Newtonian theory as an _explanation_ of them
does. For in what does the explanation consist? In ascribing those
motions to a general law which obtains between all particles of matter,
and in identifying this with the law by which bodies fall to the ground.
If the planets are kept in their orbits by a force which draws the
particles composing them towards every other particle of matter in the
solar system, they are not kept in those orbits by the impulsive force
of certain streams of matter which whirl them round. The one explanation
absolutely excludes the other. Either the planets are not moved by
vortices, or they do not move by a law common to all matter. It is
impossible that both opinions can be true. As well might it be said that
there is no contradiction between the assertions, that a man died
because somebody killed him, and that he died a natural death.
So, again, the theory that the planets move by a virtue inherent in
their celestial nature, is incompatible with either of the two others:
either that of their being moved by vortices, or that which regards them
as moving by a property which they have in common with the earth and all
terrestrial bodies. Dr. Whewell says that the theory of an inherent
virtue agrees with Newton's when the word inherent is left out, which of
course it would be (he says) if "found to be untenable." But leave that
out, and where is the theory? The word inherent _is_ the theory. When
that is omitted, there remains nothing except that the heavenly bodies
move by "a virtue," _i.e._ by a power of some sort; or by virtue of
their celestial nature, which directly contradicts the doctrine that
terrestrial bodies fall by the same law.
If Dr. Whewell is not yet satisfied, any other subject will serve
equally well to test his doctrine. He will hardly say that there is no
contradiction between the emission theory and the undulatory theory of
light; or that there can be both one and two electricities; or that the
hypothesis of the production of the higher organic forms by development
from the lower, and the supposition of separate and successive acts of
creation, are quite reconcileable; or that the theory that volcanoes are
fed from a central fire, and the doctrines which ascribe them to
chemical action at a comparatively small depth below the earth's
surface, are consistent with one another, and all true as far as they
go.
If different explanations of the same fact cannot both be true, still
less, surely, can different predictions. Dr. Whewell quarrels (on what
ground it is not necessary here to consider) with the example I had
chosen on this point, and thinks an objection to an illustration a
sufficient answer to a theory. Examples not liable to his objection are
easily found, if the proposition that conflicting predictions cannot
both be true, can be made clearer by any examples. Suppose the
phenomenon to be a newly-discovered comet, and that one astronomer
predicts its return once in every 300 years--another once in every 400:
can they both be right? When Columbus predicted that by sailing
constantly westward he should in time return to the point from which he
set out, while others asserted that he could never do so except by
turning back, were both he and his opponents true prophets? Were the
predictions which foretold the wonders of railways and steamships, and
those which averred that the Atlantic could never be crossed by steam
navigation, nor a railway train propelled ten miles an hour, both (in
Dr. Whewell's words) "true, and consistent with one another"?
Dr. Whewell sees no distinction between holding contradictory opinions
on a question of fact, and merely employing different analogies to
facilitate the conception of the same fact. The case of different
Inductions belongs to the former class, that of different Descriptions
to the latter.
[7] _Phil. of Discov._ p. 256.
[8] _Essays on the Pursuit of Truth._
[9] In the first edition a note was appended at this place, containing
some criticism on Archbishop Whately's mode of conceiving the relation
between Syllogism and Induction. In a subsequent issue of his _Logic_,
the Archbishop made a reply to the criticism, which induced me to cancel
part of the note, incorporating the remainder in the text. In a still
later edition, the Archbishop observes in a tone of something like
disapprobation, that the objections, "doubtless from their being fully
answered and found untenable, were silently suppressed," and that hence
he might appear to some of his readers to be combating a shadow. On this
latter point, the Archbishop need give himself no uneasiness. His
readers, I make bold to say, will fully credit his mere affirmation that
the objections have actually been made.
But as he seems to think that what he terms the suppression of the
objections ought not to have been made "silently," I now break that
silence, and state exactly what it is that I suppressed, and why. I
suppressed that alone which might be regarded as personal criticism on
the Archbishop. I had imputed to him the having omitted to ask himself a
particular question. I found that he had asked himself the question, and
could give it an answer consistent with his own theory. I had also,
within the compass of a parenthesis, hazarded some remarks on certain
general characteristics of Archbishop Whately as a philosopher. These
remarks, though their tone, I hope, was neither disrespectful nor
arrogant, I felt, on reconsideration, that I was hardly entitled to
make; least of all, when the instance which I had regarded as an
illustration of them, failed, as I now saw, to bear them out. The real
matter at the bottom of the whole dispute, the different view we take of
the function of the major premise, remains exactly where it was; and so
far was I from thinking that my opinion had been "fully answered" and
was "untenable," that in the same edition in which I cancelled the note,
I not only enforced the opinion by further arguments, but answered
(though without naming him) those of the Archbishop.
For not having made this statement before, I do not think it needful to
apologize. It would be attaching very great importance to one's smallest
sayings, to think a formal retractation requisite every time that one
commits an error. Nor is Archbishop Whately's well-earned fame of so
tender a quality as to require, that in withdrawing a slight criticism
on him I should have been bound to offer a public _amende_ for having
made it.
[10] But though it is a condition of the validity of every induction
that there be uniformity in the course of nature, it is not a necessary
condition that the uniformity should pervade all nature. It is enough
that it pervades the particular class of phenomena to which the
induction relates. An induction concerning the motions of the planets,
or the properties of the magnet, would not be vitiated though we were to
suppose that wind and weather are the sport of chance, provided it be
assumed that astronomical and magnetic phenomena are under the dominion
of general laws. Otherwise the early experience of mankind would have
rested on a very weak foundation; for in the infancy of science it could
not be known that _all_ phenomena are regular in their course.
Neither would it be correct to say that every induction by which we
infer any truth, implies the general fact of uniformity _as foreknown_,
even in reference to the kind of phenomena concerned. It implies,
_either_ that this general fact is already known, _or_ that we may now
know it: as the conclusion, the Duke of Wellington is mortal, drawn from
the instances A, B, and C, implies either that we have already concluded
all men to be mortal, or that we are now entitled to do so from the same
evidence. A vast amount of confusion and paralogism respecting the
grounds of Induction would be dispelled by keeping in view these simple
considerations.
[11] Infra, chap. xxi.
[12] Infra, chap. xxi. xxii.
[13] Dr. Whewell (_Phil. of Discov._ p. 246) will not allow these and
similar erroneous judgments to be called inductions; inasmuch as such
superstitious fancies "were not collected from the facts by seeking a
law of their occurrence, but were suggested by an imagination of the
anger of superior powers, shown by such deviations from the ordinary
course of nature." I conceive the question to be, not in what manner
these notions were at first suggested, but by what evidence they have,
from time to time, been supposed to be substantiated. If the believers
in these erroneous opinions had been put on their defence, they would
have referred to experience: to the comet which preceded the
assassination of Julius Cæsar, or to oracles and other prophecies known
to have been fulfilled. It is by such appeals to facts that all
analogous superstitions, even in our day, attempt to justify themselves;
the supposed evidence of experience is necessary to their hold on the
mind. I quite admit that the influence of such coincidences would not be
what it is, if strength were not lent to it by an antecedent
presumption; but this is not peculiar to such cases; preconceived
notions of probability form part of the explanation of many other cases
of belief on insufficient evidence. The _à priori_ prejudice does not
prevent the erroneous opinion from being sincerely regarded as a
legitimate conclusion from experience; though it improperly predisposes
the mind to that interpretation of experience.
Thus much in defence of the sort of examples objected to. But it would
be easy to produce instances, equally adapted to the purpose, and in
which no antecedent prejudice is at all concerned. "For many ages," says
Archbishop Whately, "all farmers and gardeners were firmly
convinced--and convinced of their knowing it by experience--that the
crops would never turn out good unless the seed were sown during the
increase of the moon." This was induction, but bad induction: just as a
vicious syllogism is reasoning, but bad reasoning.
[14] The assertion, that any and every one of the conditions of a
phenomenon may be and is, on some occasions and for some purposes,
spoken of as the cause, has been disputed by an intelligent reviewer of
this work in the _Prospective Review_ (the predecessor of the justly
esteemed _National Review_), who maintains that "we always apply the
word cause rather to that element in the antecedents which exercises
_force_, and which would _tend_ at all times to produce the same or a
similar effect to that which, under certain conditions, it would
actually produce." And he says, that "every one would feel" the
expression, that the cause of a surprise was the sentinel's being off
his post, to be incorrect; but that the "allurement or force which
_drew_ him off his post, might be so called, because in doing so it
removed a resisting power which would have prevented the surprise." I
cannot think that it would be wrong to say, that the event took place
because the sentinel was absent, and yet right to say that it took place
because he was bribed to be absent. Since the only direct effect of the
bribe was his absence, the bribe could be called the remote cause of the
surprise, only on the supposition that the absence was the proximate
cause; nor does it seem to me that any one (who had not a theory to
support) would use the one expression and reject the other.
The reviewer observes, that when a person dies of poison, his possession
of bodily organs is a necessary condition, but that no one would ever
speak of it as the cause. I admit the fact; but I believe the reason to
be, that the occasion could never arise for so speaking of it; for when
in the inaccuracy of common discourse we are led to speak of some one
condition of a phenomenon as its cause, the condition so spoken of is
always one which it is at least possible that the hearer may require to
be informed of. The possession of bodily organs is a known condition,
and to give that as the answer, when asked the cause of a person's
death, would not supply the information sought. Once conceive that a
doubt could exist as to his having bodily organs, or that he were to be
compared with some being who had them not, and cases may be imagined in
which it might be said that his possession of them was the cause of his
death. If Faust and Mephistopheles together took poison, it might be
said that Faust died because he was a human being, and had a body, while
Mephistopheles survived because he was a spirit.
It is for the same reason that no one (as the reviewer remarks) "calls
the cause of a leap, the muscles or sinews of the body, though they are
necessary conditions; nor the cause of a self-sacrifice, the knowledge
which was necessary for it; nor the cause of writing a book, that a man
has time for it, which is a necessary condition." These conditions
(besides that they are antecedent _states_, and not proximate antecedent
_events_, and are therefore never the conditions in closest apparent
proximity to the effect) are all of them so obviously implied, that it
is hardly possible there should exist that necessity for insisting on
them, which alone gives occasion for speaking of a single condition as
if it were the cause. Wherever this necessity exists in regard to some
one condition, and does not exist in regard to any other, I conceive
that it is consistent with usage, when scientific accuracy is not aimed
at, to apply the name cause to that one condition. If the only condition
which can be supposed to be unknown is a negative condition, the
negative condition may be spoken of as the cause. It might be said that
a person died for want of medical advice: though this would not be
likely to be said, unless the person was already understood to be ill,
and in order to indicate that this negative circumstance was what made
the illness fatal, and not the weakness of his constitution, or the
original virulence of the disease. It might be said that a person was
drowned because he could not swim; the positive condition, namely, that
he fell into the water, being already implied in the word drowned. And
here let me remark, that his falling into the water is in this case the
only positive condition: all the conditions not expressly or virtually
included in this (as that he could not swim, that nobody helped him, and
so forth) are negative. Yet, if it were simply said that the cause of a
man's death was falling into the water, there would be quite as great a
sense of impropriety in the expression, as there would be if it were
said that the cause was his inability to swim; because, though the one
condition is positive and the other negative, it would be felt that
neither of them was sufficient, without the other, to produce death.
With regard to the assertion that nothing is termed the cause, except
the element which exerts active force; I wave the question as to the
meaning of active force, and accepting the phrase in its popular sense,
I revert to a former example, and I ask, would it be more agreeable to
custom to say that a man fell because his foot slipped in climbing a
ladder, or that he fell because of his weight? for his weight, and not
the motion of his foot, was the active force which determined his fall.
If a person walking out in a frosty day, stumbled and fell, it might be
said that he stumbled because the ground was slippery, or because he was
not sufficiently careful; but few people, I suppose, would say, that he
stumbled because he walked. Yet the only active force concerned was that
which he exerted in walking: the others were mere negative conditions;
but they happened to be the only ones which there could be any necessity
to state; for he walked, most likely, in exactly his usual manner, and
the negative conditions made all the difference. Again, if a person were
asked why the army of Xerxes defeated that of Leonidas, he would
probably say, because they were a thousand times the number; but I do
not think he would say, it was because they fought, though that was the
element of active force. To borrow another example, used by Mr. Grove
and by Mr. Baden Powell, the opening of floodgates is said to be the
cause of the flow of water; yet the active force is exerted by the water
itself, and opening the floodgates merely supplies a negative condition.
The reviewer adds, "there are some conditions absolutely passive, and
yet absolutely necessary to physical phenomena, viz. the relations of
space and time; and to these no one ever applies the word cause without
being immediately arrested by those who hear him." Even from this
statement I am compelled to dissent. Few persons would feel it
incongruous to say (for example) that a secret became known because it
was spoken of when A. B. was within hearing; which is a condition of
space: or that the cause why one of two particular trees is taller than
the other, is that it has been longer planted; which is a condition of
time.
[15] There are a few exceptions; for there are some properties of
objects which seem to be purely preventive; as the property of opaque
bodies, by which they intercept the passage of light. This, as far as we
are able to understand it, appears an instance not of one cause
counteracting another by the same law whereby it produces its own
effects, but of an agency which manifests itself in no other way than in
defeating the effects of another agency. If we knew on what other
relations to light, or on what peculiarities of structure, opacity
depends, we might find that this is only an apparent, not a real,
exception to the general proposition in the text. In any case it needs
not affect the practical application. The formula which includes all the
negative conditions of an effect in the single one of the absence of
counteracting causes, is not violated by such cases as this; though, if
all counteracting agencies were of this description, there would be no
purpose served by employing the formula, since we should still have to
enumerate specially the negative conditions of each phenomenon, instead
of regarding them as implicitly contained in the positive laws of the
various other agencies in nature.
[16] I mean by this expression, the ultimate laws of nature (whatever
they may be) as distinguished from the derivative laws and from the
collocations. The diurnal revolution of the earth (for example) is not a
part of the constitution of things, because nothing can be so called
which might possibly be terminated or altered by natural causes.
[17] I use the words "straight line" for brevity and simplicity. In
reality the line in question is not exactly straight, for, from the
effect of refraction, we actually see the sun for a short interval
during which the opaque mass of the earth is interposed in a direct line
between the sun and our eyes; thus realizing, though but to a limited
extent, the coveted desideratum of seeing round a corner.
[18] _Second Burnett Prize Essay_, by Principal Tulloch, p. 25.
[19] _Letters on the Philosophy of the Human Mind_, First Series, p.
219.
[20] _Essays_, pp. 206-208.
[21] To the universality which mankind are agreed in ascribing to the
Law of Causation, there is one claim of exception, one disputed case,
that of the Human Will; the determinations of which, a large class of
metaphysicians are not willing to regard as following the causes called
motives, according to as strict laws as those which they suppose to
exist in the world of mere matter. This controverted point will undergo
a special examination when we come to treat particularly of the Logic of
the Moral Sciences (Book vi. ch. 2). In the mean time I may remark that
these metaphysicians, who, it must be observed, ground the main part of
their objection on the supposed repugnance of the doctrine in question
to our consciousness, seem to me to mistake the fact which consciousness
testifies against. What is really in contradiction to consciousness,
they would, I think, on strict self-examination, find to be, the
application to human actions and volitions of the ideas involved in the
common use of the term Necessity; which I agree with them in objecting
to. But if they would consider that by saying that a person's actions
_necessarily_ follow from his character, all that is really meant (for
no more is meant in any case whatever of causation) is that he
invariably _does_ act in conformity to his character, and that any one
who thoroughly knew his character would certainly predict how he would
act in any supposable case; they probably would not find this doctrine
either contrary to their experience or revolting to their feelings. And
no more than this is contended for by any one but an Asiatic fatalist.
[22] _Lectures on Metaphysics_, vol. ii. Lect. xxxix. pp. 391-2.
I regret that I cannot invoke the authority of Sir William Hamilton in
favour of my own opinions on Causation, as I can against the particular
theory which I am now combating. But that acute thinker has a theory of
Causation peculiar to himself, which has never yet, as far as I know,
been analytically examined, but which, I venture to think, admits of as
complete refutation as any one of the false or insufficient
psychological theories which strew the ground in such numbers under his
potent metaphysical scythe. (Since examined and controverted in the
sixteenth chapter of _An Examination of Sir William Hamilton's
Philosophy_).
[23] Unless we are to consider as such the following statement, by one
of the writers quoted in the text: "In the case of mental exertion, the
result to be accomplished is preconsidered or meditated, and is
therefore known _à priori_, or before experience."--(Bowen's _Lowell
Lectures on the Application of Metaphysical and Ethical Science to the
Evidence of Religion_, Boston, 1849.) This is merely saying that when we
will a thing we have an idea of it. But to have an idea of what we wish
to happen, does not imply a prophetic knowledge that it will happen.
Perhaps it will be said that the _first time_ we exerted our will, when
we had of course no experience of any of the powers residing in us, we
nevertheless must already have known that we possessed them, since we
cannot will that which we do not believe to be in our power. But the
impossibility is perhaps in the words only, and not in the facts; for we
may _desire_ what we do not know to be in our power; and finding by
experience that our bodies move according to our _desire_, we may then,
and only then, pass into the more complicated mental state which is
termed will.
After all, even if we had an instinctive knowledge that our actions
would follow our will, this, as Brown remarks, would prove nothing as to
the nature of Causation. Our knowing, previous to experience, that an
antecedent will be followed by a certain consequent, would not prove the
relation between them to be anything more than antecedence and
consequence.
[24] Reid's _Essays on the Active Powers_, Essay iv. ch. 3.
[25] _Prospective Review_ for February 1850.
[26] Vide supra, p. 270, note.
[27] _Westminster Review_ for October 1855.
[28] See the whole doctrine in Aristotle _de Animâ_: where the [Greek:
threptikê psychê] is treated as exactly equivalent to [Greek: threptikê
dynamis].
[29] It deserves notice that the parts of nature, which Aristotle
regards as presenting evidence of design, are the Uniformities: the
phenomena in so far as reducible to law. [Greek: Tychê] and [Greek: to
automaton] satisfy him as explanations of the variable element in
phenomena, but their occurring according to a fixed rule can only, to
his conceptions, be accounted for by an Intelligent Will. The common, or
what may be called the instinctive, religious interpretation of nature,
is the reverse of this. The events in which men spontaneously see the
hand of a supernatural being, are those which cannot, as they think, be
reduced to a physical law. What they can distinctly connect with
physical causes, and especially what they can predict, though of course
ascribed to an Author of Nature if they already recognise such an
author, might be conceived, they think, to arise from a blind fatality,
and in any case do not appear to them to bear so obviously the mark of a
divine will. And this distinction has been countenanced by eminent
writers on Natural Theology, in particular by Dr. Chalmers: who thinks
that though design is present everywhere, the irresistible evidence of
it is to be found not in the _laws_ of nature but in the collocations,
_i.e._ in the part of nature in which it is impossible to trace any law.
A few properties of dead matter might, he thinks, conceivably account
for the regular and invariable succession of effects and causes; but
that the different kinds of matter have been so placed as to promote
beneficent ends, is what he regards as the proof of a Divine Providence.
Mr. Baden Powell, in his Essay entitled "Philosophy of Creation," has
returned to the point of view of Aristotle and the ancients, and
vigorously reasserts the doctrine that the indication of design in the
universe is not special adaptations, but Uniformity and Law, these being
the evidences of mind, and not what appears to us to be a provision for
our uses. While I decline to express any opinion here on this _vexata
quæstio_, I ought not to mention Mr. Powell's volume without the
acknowledgment due to the philosophic spirit which pervades generally
the three Essays composing it, forming in the case of one of them (the
"Unity of Worlds") an honourable contrast with the other dissertations,
so far as they have come under my notice, which have appeared on either
side of that controversy.
[30] In the words of Fontenelle, another celebrated Cartesian, "les
philosophes aussi bien que le peuple avaient cru que l'âme et le corps
agissaient réellement et physiquement l'un sur l'autre. Descartes vint,
qui prouva que leur nature ne permettait point cette sorte de
communication véritable, et qu'ils n'en pouvaient avoir qu'une
apparente, dont Dieu était le Médiateur."--_Oeuvres de Fontenelle_,
ed. 1767, tom. v. p. 534.
[31] I omit, for simplicity, to take into account the effect, in this
latter case, of the diminution of pressure, in diminishing the flow of
water through the drain; which evidently in no way affects the truth or
applicability of the principle, since when the two causes act
simultaneously the conditions of that diminution of pressure do not
arise.
[32] Unless, indeed, the consequent was generated not by the antecedent,
but by the means employed to produce the antecedent. As, however, these
means are under our power, there is so far a probability that they are
also sufficiently within our knowledge, to enable us to judge whether
that could be the case or not.
[33] _Discourse on the Study of Natural Philosophy_, p. 179.
[34] For this speculation, as for many other of my scientific
illustrations, I am indebted to Professor Bain, of Aberdeen, who has
since, in his profound treatises entitled "The Senses and the
Intellect," and "The Emotions and the Will," carried the analytic
investigation of the mental phenomena according to the methods of
physical science, to the most advanced point which it has yet reached,
and has worthily inscribed his name among the successive constructors of
an edifice to which Hartley, Brown, and James Mill had each contributed
their part.
[35] This view of the necessary coexistence of opposite excitements
involves a great extension of the original doctrine of two
electricities. The early theorists assumed that, when amber was rubbed,
the amber was made positive and the rubber negative to the same degree;
but it never occurred to them to suppose that the existence of the amber
charge was dependent on an opposite charge in the bodies with which the
amber was contiguous, while the existence of the negative charge on the
rubber was equally dependent on a contrary state of the surfaces that
might accidentally be confronted with it; that, in fact, in a case of
electrical excitement by friction, four charges were the minimum that
could exist. But this double electrical action is essentially implied in
the explanation now universally adopted in regard to the phenomena of
the common electric machine.
[36] Pp. 159-162.
[37] Infra, book iv. ch. ii. On Abstraction.
[38] I must, however, remark, that this example, which seems to militate
against the assertion we made of the comparative inapplicability of the
Method of Difference to cases of pure observation, is really one of
those exceptions which, according to a proverbial expression, prove the
general rule. For in this case, in which Nature, in her experiment,
seems to have imitated the type of the experiments made by man, she has
only succeeded in producing the likeness of man's most imperfect
experiments; namely, those in which, though he succeeds in producing the
phenomenon, he does so by employing complex means, which he is unable
perfectly to analyse, and can form therefore no sufficient judgment what
portion of the effects may be due, not to the supposed cause, but to
some unknown agency of the means by which that cause was produced. In
the natural experiment which we are speaking of, the means used was the
clearing off a canopy of clouds; and we certainly do not know
sufficiently in what this process consists, or on what it depends, to be
certain _à priori_ that it might not operate upon the deposition of dew
independently of any thermometric effect at the earth's surface. Even,
therefore, in a case so favourable as this to Nature's experimental
talents, her experiment is of little value except in corroboration of a
conclusion already attained through other means.
[39] In his subsequent work, _Outlines of Astronomy_ (§ 570), Sir John
Herschel suggests another possible explanation of the acceleration of
the revolution of a comet.
[40] Discourse, pp. 156-8, and 171.
[41] _Outlines of Astronomy_, § 856.
[42] _Philosophy of Discovery_, pp. 263, 264.
[43] See, on this point, the second chapter of the present Book.
[44] Ante, ch. vii. § 1.
[45] It seems hardly necessary to say that the word _impinge_, as a
general term to express collision of forces, is here used by a figure of
speech, and not as expressive of any theory respecting the nature of
force.
[46] _Essays on some Unsettled Questions of Political Economy_, Essay V.
[47] _Vide_ Memoir by Thomas Graham, F.R.S., Master of the Mint, "On
Liquid Diffusion Applied to Analysis," in the _Philosophical
Transactions_ for 1862, reprinted in the _Journal of the Chemical
Society_, and also separately as a pamphlet.
[48] It was an old generalization in surgery, that tight bandaging had a
tendency to prevent or dissipate local inflammation. This sequence,
being, in the progress of physiological knowledge, resolved into more
general laws, led to the important surgical invention made by Dr.
Arnott, the treatment of local inflammation and tumours by means of an
equable pressure, produced by a bladder partially filled with air. The
pressure, by keeping back the blood from the part, prevents the
inflammation, or the tumour, from being nourished: in the case of
inflammation, it removes the stimulus, which the organ is unfit to
receive; in the case of tumours, by keeping back the nutritive fluid, it
causes the absorption of matter to exceed the supply, and the diseased
mass is gradually absorbed and disappears.
[49] Since acknowledged and reprinted in Mr. Martineau's _Miscellanies_.
[50] _Dissertations and Discussions_, vol. i., fourth paper.
[51] Written before the rise of the new views respecting the relation of
heat to mechanical force; but confirmed rather than contradicted by
them.
END OF VOL. I.
LONDON:
SAVILL, EDWARDS AND CO., PRINTERS, CHANDOS STREET,
COVENT GARDEN.
Transcriber's Notes
Spelling irregularities where there was no obviously preferred version
were left as is. Variants include: "alkalies" and "alkalis;" "apprise"
and "apprize;" "coexistent" and "co-existent" (along with derivatives);
"coextensive" and "co-extensive;" "e. g." and "e.g."; "encumbered" and
"incumbered;" "formulæ" and "formulas;" "i. e." and "i.e."; "nonentity"
and "non-entity;" "recal" and "recall" (and derivatives); "rectilinear"
and "rectilineal;" "stopt" and "stopped."
Changed "3" to "4" on page xiii: "4. --and from descriptions."
Inserted missing page number, "167," for Chapter VIII, section 7 on page
xiii.
Moved the semi-colon inside the quotation marks in the footnote on page
14: "the Science of the Formal Laws of Thought;".
Changed "sub-divisions" to "subdivisions" on page 59: "three
subdivisions."
Changed "pre-supposed" to "presupposed" on page 75: "they are
presupposed."
In the footnote to page 122, changed the Greek character upsilon with
dasia and oxia to upsilon with psili and oxia, making the
transliteration "deuterai ousiai."
Changed "he" to "be" on page 189: "to which it may be reduced."
Changed "cb." to "ch." in footnote on page 227: "Theory of Reasoning,
ch. iv."
Changed "reconcilable" to "reconcileable" on page 240: "not easily
reconcileable."
Preserved the hyphen in "counter-acting" on page 280. Usually this is
spelled without the hyphen, but this instance is in a quotation.
Moved parenthesis that was after "to" to before it on page 321: "(to
return to a former example)."
Put "i.e." in italics on page 335: "_i.e._ by a power of some sort."
Changed "paralyzed" to "paralysed" on page 389: "nerves of motion were
paralysed."
The footnote from page 396 refers to the footnote on page 270. There is
no such footnote. The intent may be to refer to the footnote on page
268. However, the text was not changed.
Added the dropped "w" in "which" on page 420: "which the progress of the
inquiry."
Changed "developes" to "develops" on page 456: "the prime conductor
develops."
Removed the additional period at the end of the footnote on page 457:
"Pp. 159-162."
Added the dropped "l" to "essential" on page 515: "an essential
requisite."
Removed extra opening quotation mark before "gum" on page 532:
"vegetable gum is not digested."
In the Latin-1 text version, the oe-ligature was replaced by the two
characters, "oe" (or "Oe" when capitalized).