§ 1. Induction, then, is that operation of the mind, by which we infer
that what we know to be true in a particular case or cases, will be true
in all cases which resemble the former in certain assignable respects. In
other words, Induction is the process by which we conclude that what is
true of certain individuals of a class is true of the whole class, or that
what is true at certain times will be true in similar circumstances at all
times.
This definition excludes from the meaning of the term Induction, various
logical operations, to which it is not unusual to apply that name.
Induction, as above defined, is a process of inference; it proceeds from
the known to the unknown; and any operation involving no inference, any
process in which what seems the conclusion is no wider than the premisses
from which it is drawn, does not fall within the meaning of the term. Yet
in the common books of Logic we find this laid down as the most perfect,
indeed the only quite perfect, form of induction. In those books, every
process which sets out from a less general and terminates in a more
general expression,—which admits of being stated in the form, “This and
that A are B, therefore every A is B,”—is called an induction, whether
anything be really concluded or not; and the induction is asserted to be
not perfect, unless every single individual of the class A is included in
the antecedent, or premiss: that is, unless what we affirm of the class
has already been ascertained to be true of every individual in it, so that
the nominal conclusion is not really a conclusion, but a mere reassertion
of the premisses. If we were to say, All the planets shine by the sun’s
light, from observation of each separate planet, or All the Apostles were
Jews, because this is true of Peter, Paul, John, and every other
apostle,—these, and such as these, would, in the phraseology in question,
be called perfect, and the only perfect, Inductions. This, however, is a
totally different kind of induction from ours; it is no inference from
facts known to facts unknown, but a mere short-hand registration of facts
known. The two simulated arguments which we have quoted, are not
generalizations; the propositions purporting to be conclusions from them,
are not really general propositions. A general proposition is one in which
the predicate is affirmed or denied of an unlimited number of individuals;
namely, all, whether few or many, existing or capable of existing, which
possess the properties connoted by the subject of the proposition. “All
men are mortal” does not mean all now living, but all men past, present,
and to come. When the signification of the term is limited so as to render
it a name not for any and every individual falling under a certain general
description, but only for each of a number of individuals designated as
such, and as it were counted off individually, the proposition, though it
may be general in its language, is no general proposition, but merely that
number of singular propositions, written in an abridged character. The
operation may be very useful, as most forms of abridged notation are; but
it is no part of the investigation of truth, though often bearing an
important part in the preparation of the materials for that investigation.
§ 2. A second process which requires to be distinguished from Induction,
is one to which mathematicians sometimes give that name: and which so far
resembles Induction properly so called, that the propositions it leads to
are really general propositions. For example, when we have proved with
respect to the circle, that a straight line cannot meet it in more than
two points, and when the same thing has been successively proved of the
ellipse, the parabola, and the hyperbola, it may be laid down as an
universal property of the sections of the cone. In this example there is
no induction, because there is no inference: the conclusion is a mere
summing up of what was asserted in the various propositions from which it
is drawn. A case somewhat, though not altogether, similar, is the proof of
a geometrical theorem by means of a diagram. Whether the diagram be on
paper or only in the imagination, the demonstration (as formerly
observed(54)) does not prove directly the general theorem; it proves only
that the conclusion, which the theorem asserts generally, is true of the
particular triangle or circle exhibited in the diagram; but since we
perceive that in the same way in which we have proved it of that circle,
it might also be proved of any other circle, we gather up into one general
expression all the singular propositions susceptible of being thus proved,
and embody them in an universal proposition. Having shown that the three
angles of the triangle ABC are together equal to two right angles, we
conclude that this is true of every other triangle, not because it is true
of ABC, but for the same reason which proved it to be true of ABC. If this
were to be called Induction, an appropriate name for it would be,
induction by parity of reasoning. But the term cannot properly belong to
it; the characteristic quality of Induction is wanting, since the truth
obtained, though really general, is not believed on the evidence of
particular instances. We do not conclude that all triangles have the
property because some triangles have, but from the ulterior demonstrative
evidence which was the ground of our conviction in the particular
instances.
There are nevertheless, in mathematics, some examples of so-called
induction, in which the conclusion does bear the appearance of a
generalization grounded on some of the particular cases included in it. A
mathematician, when he has calculated a sufficient number of the terms of
an algebraical or arithmetical series to have ascertained what is called
the _law_ of the series, does not hesitate to fill up any number of the
succeeding terms without repeating the calculations. But I apprehend he
only does so when it is apparent from _à priori_ considerations (which
might be exhibited in the form of demonstration) that the mode of
formation of the subsequent terms, each from that which preceded it, must
be similar to the formation of the terms which have been already
calculated. And when the attempt has been hazarded without the sanction of
such general considerations, there are instances on record in which it has
led to false results.
It is said that Newton discovered the binomial theorem by induction; by
raising a binomial successively to a certain number of powers, and
comparing those powers with one another until he detected the relation in
which the algebraic formula of each power stands to the exponent of that
power, and to the two terms of the binomial. The fact is not improbable:
but a mathematician like Newton, who seemed to arrive _per saltum_ at
principles and conclusions that ordinary mathematicians only reached by a
succession of steps, certainly could not have performed the comparison in
question without being led by it to the _à priori_ ground of the law;
since any one who understands sufficiently the nature of multiplication to
venture upon multiplying several lines of symbols at one operation, cannot
but perceive that in raising a binomial to a power, the coefficients must
depend on the laws of permutation and combination: and as soon as this is
recognised, the theorem is demonstrated. Indeed, when once it was seen
that the law prevailed in a few of the lower powers, its identity with the
law of permutation would at once suggest the considerations which prove it
to obtain universally. Even, therefore, such cases as these, are but
examples of what I have called induction by parity of reasoning, that is,
not really induction, because not involving inference of a general
proposition from particular instances.
§ 3. There remains a third improper use of the term Induction, which it is
of real importance to clear up, because the theory of induction has been,
in no ordinary degree, confused by it, and because the confusion is
exemplified in the most recent and most elaborate treatise on the
inductive philosophy which exists in our language. The error in question
is that of confounding a mere description of a set of observed phenomena,
with an induction from them.
Suppose that a phenomenon consists of parts, and that these parts are only
capable of being observed separately, and as it were piecemeal. When the
observations have been made, there is a convenience (amounting for many
purposes to a necessity) in obtaining a representation of the phenomenon
as a whole, by combining, or as we may say, piecing these detached
fragments together. A navigator sailing in the midst of the ocean
discovers land: he cannot at first, or by any one observation, determine
whether it is a continent or an island; but he coasts along it, and after
a few days finds himself to have sailed completely round it: he then
pronounces it an island. Now there was no particular time or place of
observation at which he could perceive that this land was entirely
surrounded by water: he ascertained the fact by a succession of partial
observations, and then selected a general expression which summed up in
two or three words the whole of what he so observed. But is there anything
of the nature of an induction in this process? Did he infer anything that
had not been observed, from something else which had? Certainly not. He
had observed the whole of what the proposition asserts. That the land in
question is an island, is not an inference from the partial facts which
the navigator saw in the course of his circumnavigation; it is the facts
themselves; it is a summary of those facts; the description of a complex
fact, to which those simpler ones are as the parts of a whole.
Now there is, I conceive, no difference in kind between this simple
operation, and that by which Kepler ascertained the nature of the
planetary orbits: and Kepler’s operation, all at least that was
characteristic in it, was not more an inductive act than that of our
supposed navigator.
The object of Kepler was to determine the real path described by each of
the planets, or let us say by the planet Mars, (for it was of that body
that he first established two of the three great astronomical truths which
bear his name.) To do this there was no other mode than that of direct
observation: and all which observation could do was to ascertain a great
number of the successive places of the planet; or rather, of its apparent
places. That the planet occupied successively all these positions, or at
all events, positions which produced the same impressions on the eye, and
that it passed from one of these to another insensibly, and without any
apparent breach of continuity; thus much the senses, with the aid of the
proper instruments, could ascertain. What Kepler did more than this, was
to find what sort of a curve these different points would make, supposing
them to be all joined together. He expressed the whole series of the
observed places of Mars by what Dr. Whewell calls the general conception
of an ellipse. This operation was far from being as easy as that of the
navigator who expressed the series of his observations on successive
points of the coast by the general conception of an island. But it is the
very same sort of operation; and if the one is not an induction but a
description, this must also be true of the other.
To avoid misapprehension, we must remark that Kepler, in one respect,
performed a real act of induction; namely, in concluding that because the
observed places of Mars were correctly represented by points in an
imaginary ellipse, therefore Mars would continue to revolve in that same
ellipse; and even in concluding that the position of the planet during the
time which intervened between two observations, must have coincided with
the intermediate points of the curve. But this really inductive operation
requires to be carefully distinguished from the mere act of bringing the
facts actually observed under a general description. So distinct are these
two operations, that the one might have been performed without the other.
Men might and did make correct inductions concerning the heavenly motions,
before they had obtained correct general descriptions of them. It was
known that the planets always moved in the same paths, long before it had
been ascertained that those paths were ellipses. Astronomers early
remarked that the same set of apparent positions returned periodically.
When they obtained a new description of the phenomenon, they did not
necessarily make any further induction, nor (which is the true test of a
new general truth) add anything to the power of prediction which they
already possessed.
§ 4. The descriptive operation which enables a number of details to be
summed up in a single proposition, Dr. Whewell, by an aptly chosen
expression, has termed the Colligation of Facts.(55) In most of his
observations concerning that mental process I fully agree, and would
gladly transfer all that portion of his book into my own pages. I only
think him mistaken in setting up this kind of operation, which according
to the old and received meaning of the term, is not induction at all, as
the type of induction generally; and laying down, throughout his work, as
principles of induction, the principles of mere colligation.
Dr. Whewell maintains that the general proposition which binds together
the particular facts, and makes them, as it were, one fact, is not the
mere sum of those facts, but something more, since there is introduced a
conception of the mind, which did not exist in the facts themselves. “The
particular facts,” says he,(56) “are not merely brought together, but
there is a new element added to the combination by the very act of thought
by which they are combined.... When the Greeks, after long observing the
motions of the planets, saw that these motions might be rightly considered
as produced by the motion of one wheel revolving in the inside of another
wheel, these wheels were creations of their minds, added to the facts
which they perceived by sense. And even if the wheels were no longer
supposed to be material, but were reduced to mere geometrical spheres or
circles, they were not the less products of the mind alone,—something
additional to the facts observed. The same is the case in all other
discoveries. The facts are known, but they are insulated and unconnected,
till the discoverer supplies from his own store a principle of connexion.
The pearls are there, but they will not hang together till some one
provides the string.”
That a conception of the mind is introduced is indeed undeniable, and I
willingly concede, that to hit upon the right conception is often a far
more difficult and more meritorious achievement, than to prove its
applicability when obtained. But a conception implies, and corresponds to,
something conceived: and though the conception itself is not in the facts,
but in our mind, it must be a conception _of_ something which really is in
the facts, some property which they actually possess, and which they would
manifest to our senses, if our senses were able to take cognizance of
them. If, for instance, the planet left behind it in space a visible
track, and if the observer were in a fixed position at such a distance
above the plane of the orbit as would enable him to see the whole of it at
once, he would see it to be an ellipse; and if gifted with appropriate
instruments, and powers of locomotion, he could prove it to be such by
measuring its different dimensions. These things are indeed impossible to
us, but not impossible in themselves; if they were so, Kepler’s law could
not be true.
Subject to the indispensable condition which has just been stated, I
cannot perceive that the part which conceptions have in the operation of
studying facts, has ever been overlooked or undervalued. No one ever
disputed that in order to reason about anything we must have a conception
of it; or that when we include a multitude of things under a general
expression, there is implied in the expression a conception of something
common to those things. But it by no means follows that the conception is
necessarily pre-existent, or constructed by the mind out of its own
materials. If the facts are rightly classed under the conception, it is
because there is in the facts themselves something of which the conception
is itself a copy; and which if we cannot directly perceive, it is because
of the limited power of our organs, and not because the thing itself is
not there. The conception itself is often obtained by abstraction from the
very facts which, in Dr. Whewell’s language, it is afterwards called in to
connect. This he himself admits, when he observes, (which he does on
several occasions,) how great a service would be rendered to the science
of physiology by the philosopher “who should establish a precise, tenable,
and consistent conception of life.”(57) Such a conception _can_ only be
abstracted from the phenomena of life itself; from the very facts which it
is put in requisition to connect. In other cases (no doubt) instead of
collecting the conception from the very phenomena which we are attempting
to colligate, we select it from among those which have been previously
collected by abstraction from other facts. In the instance of Kepler’s
laws, the latter was the case. The facts being out of the reach of being
observed, in any such manner as would have enabled the senses to identify
directly the path of the planet, the conception requisite for framing a
general description of that path could not be collected by abstraction
from the observations themselves; the mind had to supply hypothetically,
from among the conceptions it had obtained from other portions of its
experience, some one which would correctly represent the series of the
observed facts. It had to frame a supposition respecting the general
course of the phenomenon, and ask itself, If this be the general
description, what will the details be? and then compare these with the
details actually observed. If they agreed, the hypothesis would serve for
a description of the phenomenon: if not, it was necessarily abandoned, and
another tried. It is such a case as this which gives rise to the doctrine
that the mind, in framing the descriptions, adds something of its own
which it does not find in the facts.
Yet it is a fact surely, that the planet does describe an ellipse; and a
fact which we could see, if we had adequate visual organs and a suitable
position. Not having these advantages, but possessing the conception of an
ellipse, or (to express the meaning in less technical language) knowing
what an ellipse was, Kepler tried whether the observed places of the
planet were consistent with such a path. He found they were so; and he,
consequently, asserted as a fact that the planet moved in an ellipse. But
this fact, which Kepler did not add to, but found in, the motions of the
planet, namely, that it occupied in succession the various points in the
circumference of a given ellipse, was the very fact, the separate parts of
which had been separately observed; it was the sum of the different
observations.
Having stated this fundamental difference between my opinion and that of
Dr. Whewell, I must add, that his account of the manner in which a
conception is selected, suitable to express the facts, appears to me
perfectly just. The experience of all thinkers will, I believe, testify
that the process is tentative; that it consists of a succession of
guesses; many being rejected, until one at last occurs fit to be chosen.
We know from Kepler himself that before hitting upon the “conception” of
an ellipse, he tried nineteen other imaginary paths, which, finding them
inconsistent with the observations, he was obliged to reject. But as Dr.
Whewell truly says, the successful hypothesis, though a guess, ought
generally to be called, not a lucky, but a skilful guess. The guesses
which serve to give mental unity and wholeness to a chaos of scattered
particulars, are accidents which rarely occur to any minds but those
abounding in knowledge and disciplined in intellectual combinations.
How far this tentative method, so indispensable as a means to the
colligation of facts for purposes of description, admits of application to
Induction itself, and what functions belong to it in that department, will
be considered in the chapter of the present Book which relates to
Hypotheses. On the present occasion we have chiefly to distinguish this
process of Colligation from Induction properly so called: and that the
distinction may be made clearer, it is well to advert to a curious and
interesting remark, which is as strikingly true of the former operation,
as it appears to me unequivocally false of the latter.
In different stages of the progress of knowledge, philosophers have
employed, for the colligation of the same order of facts, different
conceptions. The early rude observations of the heavenly bodies, in which
minute precision was neither attained nor sought, presented nothing
inconsistent with the representation of the path of a planet as an exact
circle, having the earth for its centre. As observations increased in
accuracy, and facts were disclosed which were not reconcileable with this
simple supposition; for the colligation of those additional facts, the
supposition was varied; and varied again and again as facts became more
numerous and precise. The earth was removed from the centre to some other
point within the circle; the planet was supposed to revolve in a smaller
circle called an epicycle, round an imaginary point which revolved in a
circle round the earth: in proportion as observation elicited fresh facts
contradictory to these representations, other epicycles and other
excentrics were added, producing additional complication; until at last
Kepler swept all these circles away, and substituted the conception of an
exact ellipse. Even this is found not to represent with complete
correctness the accurate observations of the present day, which disclose
many slight deviations from an orbit exactly elliptical. Now Dr. Whewell
has remarked that these successive general expressions, though apparently
so conflicting, were all correct: they all answered the purpose of
colligation: they all enabled the mind to represent to itself with
facility, and by a simultaneous glance, the whole body of facts at that
time ascertained; each in its turn served as a correct description of the
phenomena, so far as the senses had up to that time taken cognizance of
them. If a necessity afterwards arose for discarding one of these general
descriptions of the planet’s orbit, and framing a different imaginary
line, by which to express the series of observed positions, it was because
a number of new facts had now been added, which it was necessary to
combine with the old facts into one general description. But this did not
affect the correctness of the former expression, considered as a general
statement of the only facts which it was intended to represent. And so
true is this, that, as is well remarked by M. Comte, these ancient
generalizations, even the rudest and most imperfect of them, that of
uniform movement in a circle, are so far from being entirely false, that
they are even now habitually employed by astronomers when only a rough
approximation to correctness is required. “L’astronomie moderne, en
détruisant sans retour les hypothèses primitives, envisagées comme lois
réelles du monde, a soigneusement maintenu leur valeur positive et
permanente, la propriété de représenter commodément les phénomènes quand
il s’agit d’une première ébauche. Nos ressources à cet égard sont même
bien plus étendues, precisément à cause que nous ne nous faisons aucune
illusion sur la réalité des hypothèses; ce qui nous permet d’employer sans
scrupule, en chaque cas, celle que nous jugeons la plus avantageuse.”(58)
Dr. Whewell’s remark, therefore, is philosophically correct. Successive
expressions for the colligation of observed facts, or, in other words,
successive descriptions of a phenomenon as a whole, which has been
observed only in parts, may, though conflicting, be all correct as far as
they go. But it would surely be absurd to assert this of conflicting
inductions.
The scientific study of facts may be undertaken for three different
purposes: the simple description of the facts; their explanation; or their
prediction: meaning by prediction, the determination of the conditions
under which similar facts may be expected again to occur. To the first of
these three operations the name of Induction does not properly belong: to
the other two it does. Now, Dr. Whewell’s observation is true of the first
alone. Considered as a mere description, the circular theory of the
heavenly motions represents perfectly well their general features: and by
adding epicycles without limit, those motions, even as now known to us,
might be expressed with any degree of accuracy that might be required. The
elliptical theory, as a mere description, would have a great advantage in
point of simplicity, and in the consequent facility of conceiving it and
reasoning about it; but it would not really be more true than the other.
Different descriptions, therefore, may be all true: but not, surely,
different explanations. The doctrine that the heavenly bodies moved by a
virtue inherent in their celestial nature; the doctrine that they were
moved by impact, (which led to the hypothesis of vortices as the only
impelling force capable of whirling bodies in circles,) and the Newtonian
doctrine, that they are moved by the composition of a centripetal with an
original projectile force; all these are explanations, collected by real
induction from supposed parallel cases; and they were all successively
received by philosophers, as scientific truths on the subject of the
heavenly bodies. Can it be said of these, as was said of the different
descriptions, that they are all true as far as they go? Is it not clear
that one only can be true in any degree, and the other two must be
altogether false? So much for explanations: let us now compare different
predictions: the first, that eclipses will occur whenever one planet or
satellite is so situated as to cast its shadow upon another; the second,
that they will occur whenever some great calamity is impending over
mankind. Do these two doctrines only differ in the degree of their truth,
as expressing real facts with unequal degrees of accuracy? Assuredly the
one is true, and the other absolutely false.(59)
In every way, therefore, it is evident that to explain induction as the
colligation of facts by means of appropriate conceptions, that is,
conceptions which will really express them, is to confound mere
description of the observed facts with inference from those facts, and
ascribe to the latter what is a characteristic property of the former.
There is, however, between Colligation and Induction, a real correlation,
which it is important to conceive correctly. Colligation is not always
induction; but induction is always colligation. The assertion that the
planets move in ellipses, was but a mode of representing observed facts;
it was but a colligation; while the assertion that they are drawn, or
tend, towards the sun, was the statement of a new fact, inferred by
induction. But the induction, once made, accomplishes the purposes of
colligation likewise. It brings the same facts, which Kepler had connected
by his conception of an ellipse, under the additional conception of bodies
acted upon by a central force, and serves therefore as a new bond of
connexion for those facts; a new principle for their classification.
Further, that general description, which is improperly confounded with
induction, is nevertheless a necessary preparation for induction; no less
necessary than correct observation of the facts themselves. Without the
previous colligation of detached observations by means of one general
conception, we could never have obtained any basis for an induction,
except in the case of phenomena of very limited compass. We should not be
able to affirm any predicates at all, of a subject incapable of being
observed otherwise than piecemeal: much less could we extend those
predicates by induction to other similar subjects. Induction, therefore,
always presupposes, not only that the necessary observations are made with
the necessary accuracy, but also that the results of these observations
are, so far as practicable, connected together by general descriptions,
enabling the mind to represent to itself as wholes whatever phenomena are
capable of being so represented.
§ 5. Dr. Whewell has replied at some length to the preceding observations,
re-stating his opinions, but without (as far as I can perceive) adding
anything to his former arguments. Since, however, mine have not had the
good fortune to make any impression upon him, I will subjoin a few
remarks, tending to shew more clearly in what our difference of opinion
consists, as well as, in some measure, to account for it.
All the definitions of induction, by writers of authority, make it consist
in drawing inferences from known cases to unknown; affirming of a class, a
predicate which has been found true of some cases belonging to the class;
concluding, because some things have a certain property, that other things
which resemble them have the same property—or because a thing has
manifested a property at a certain time, that it has and will have that
property at other times.
It will scarcely be contended that Kepler’s operation was an Induction in
this sense of the term. The statement, that Mars moves in an elliptical
orbit, was no generalization from individual cases to a class of cases.
Neither was it an extension to all time, of what had been found true at
some particular time. The whole amount of generalization which the case
admitted of, was already completed, or might have been so. Long before the
elliptic theory was thought of, it had been ascertained that the planets
returned periodically to the same apparent places; the series of these
places was, or might have been, completely determined, and the apparent
course of each planet marked out on the celestial globe in an
uninterrupted line. Kepler did not extend an observed truth to other cases
than those in which it had been observed: he did not widen the _subject_
of the proposition which expressed the observed facts. He left the subject
as it was; the alteration he made was in the predicate. Instead of saying,
the successive places of Mars are so and so, he summed them up in the
statement, that the successive places of Mars are points in an ellipse. It
is true, this statement, as Dr. Whewell says, was not the sum of the
observations _merely_; it was the sum of the observations _seen under a
new point of view_.(60) But it was not the sum of _more_ than the
observations, as a real induction is. It took in no cases but those which
had been actually observed, or which could have been inferred from the
observations before the new point of view presented itself. There was not
that transition from known cases to unknown, which constitutes Induction
in the original and acknowledged meaning of the term.
Old definitions, it is true, cannot prevail against new knowledge: and if
the Keplerian operation, as a logical process, were really identical with
what takes place in acknowledged induction, the definition of induction
ought to be so widened as to take it in; since scientific language ought
to adapt itself to the true relations which subsist between the things it
is employed to designate. Here then it is that I join issue with Dr.
Whewell. He does think the operations identical. He allows of no logical
process in any case of induction, other than what there was in Kepler’s
case, namely, guessing until a guess is found which tallies with the
facts: and accordingly, as we shall see hereafter, he rejects all canons
of induction, because it is not by means of them that we guess. Dr.
Whewell’s theory of the logic of science would be very perfect, if it did
not pass over altogether the question of Proof. But in my apprehension
there is such a thing as proof, and inductions differ altogether from
descriptions in their relation to that element. Induction is proof; it is
inferring something unobserved from something observed: it requires,
therefore, an appropriate test of proof; and to provide that test, is the
special purpose of inductive logic. When, on the contrary, we merely
collate known observations, and, in Dr. Whewell’s phraseology, connect
them by means of a new conception; if the conception does but serve to
connect the observations, we have all we want. As the proposition in which
it is embodied pretends to no other truth than what it may share with many
other modes of representing the same facts, to be consistent with the
facts is all it requires: it neither needs nor admits of proof; though it
may serve to prove other things, inasmuch as, by placing the facts in
mental connexion with other facts, not previously seen to resemble them,
it assimilates the case to another class of phenomena, concerning which
real Inductions have already been made. Thus Kepler’s so-called law
brought the orbit of Mars into the class ellipse, and by doing so, proved
all the properties of an ellipse to be true of the orbit: but in this
proof Kepler’s law supplied the minor premiss, and not (as is the case
with real Inductions) the major.
The mental operation which extracts from a number of detached observations
certain general characters in which the observed phenomena resemble one
another, or resemble other known facts, is what Bacon, Locke, and most
subsequent metaphysicians, have understood by the word Abstraction. A
general expression obtained by abstraction, connecting known facts by
means of common characters, but without concluding from them to unknown,
may, I think, with strict logical correctness, be termed a Description;
nor do I know in what other way things can ever be described. My position,
however, does not depend on the employment of that particular word; I am
quite content to use Dr. Whewell’s term Colligation, provided it be
clearly seen that the process is not Induction, but something radically
different.
What more may usefully be said on the subject of Colligation, or of the
correlative expression invented by Dr. Whewell, the Explication of
Conceptions, and generally on the subject of ideas and mental
representations as connected with the study of facts, will find a more
appropriate place in the Fourth Book, on the Operations Subsidiary to
Induction: to which the reader must refer for the removal of any
difficulty which the present discussion may have left.