THE ORIGIN OF THE IMPRESSIONS.
Admitting that the sensations, the feelings of pleasure and pain, and
those of relation, are the primary irresolvable states of consciousness,
two further lines of investigation present themselves. The one leads us
to seek the origin of these "impressions;" the other, to inquire into
the nature of the steps by which they become metamorphosed into those
compound states of consciousness, which so largely enter into our
ordinary trains of thought.
With respect to the origin of impressions of sensation, Hume is not
quite consistent with himself. In one place (I. p. 117) he says, that it
is impossible to decide "whether they arise immediately from the object,
or are produced by the creative power of the mind, or are derived from
the Author of our being," thereby implying that realism and idealism are
equally probable hypotheses. But, in fact, after the demonstration by
Descartes, that the immediate antecedents of sensations are changes in
the nervous system, with which our feelings have no sort of resemblance,
the hypothesis that sensations "arise immediately from the object" was
out of court; and that Hume fully admitted the Cartesian doctrine is
apparent when he says (I. p. 272):--
"All our perceptions are dependent on our organs and the
disposition of our nerves and animal spirits."
And again, though in relation to another question, he observes:--
"There are three different kinds of impressions conveyed by the
senses. The first are those of the figure, bulk, motion, and
solidity of bodies. The second those of colours, tastes, smells,
sounds, heat, and cold. The third are the pains and pleasures that
arise from the application of objects to our bodies, as by the
cutting of our flesh with steel, and such like. Both philosophers
and the vulgar suppose the first of these to have a distinct
continued existence. The vulgar only regard the second as on the
same footing. Both philosophers and the vulgar again esteem the
third to be merely perceptions, and consequently interrupted and
dependent beings.
"Now 'tis evident that, whatever may be our philosophical opinion,
colour, sounds, heat, and cold, as far as appears to the senses,
exist after the same manner with motion and solidity; and that the
difference we make between them, in this respect, arises not from
the mere perception. So strong is the prejudice for the distinct
continued existence of the former qualities, that when the contrary
opinion is advanced by modern philosophers, people imagine they can
almost refute it from their reason and experience, and that their
very senses contradict this philosophy. 'Tis also evident that
colours, sounds, &c., are originally on the same footing with the
pain that arises from steel, and pleasure that proceeds from a
fire; and that the difference betwixt them is founded neither on
perception nor reason, but on the imagination. For as they are
confessed to be, both of them, nothing but perceptions arising from
the particular configurations and motions of the parts of body,
wherein possibly can their difference consist? Upon the whole,
then, we may conclude that, as far as the senses are judges, all
perceptions are the same in the manner of their existence."--(I. p.
250, 251.)
The last words of this passage are as much Berkeley's as Hume's. But,
instead of following Berkeley in his deductions from the position thus
laid down, Hume, as the preceding citation shows, fully adopted the
conclusion to which all that we know of psychological physiology tends,
that the origin of the elements of consciousness, no less than that of
all its other states, is to be sought in bodily changes, the seat of
which can only be placed in the brain. And, as Locke had already done
with less effect, he states and refutes the arguments commonly brought
against the possibility of a causal connexion between the modes of
motion of the cerebral substance and states of consciousness, with great
clearness:--
"From these hypotheses concerning the _substance_ and _local
conjunction_ of our perceptions we may pass to another, which is
more intelligible than the former, and more important than the
latter, viz. concerning the _cause_ of our perceptions. Matter and
motion, 'tis commonly said in the schools, however varied, are
still matter and motion, and produce only a difference in the
position and situation of objects. Divide a body as often as you
please, 'tis still body. Place it in any figure, nothing ever
results but figure, or the relation of parts. Move it in any
manner, you still find motion or a change of relation. 'Tis absurd
to imagine that motion in a circle, for instance, should be nothing
but merely motion in a circle; while motion in another direction,
as in an ellipse, should also be a passion or moral reflection;
that the shocking of two globular particles should become a
sensation of pain, and that the meeting of the triangular ones
should afford a pleasure. Now as these different shocks and
variations and mixtures are the only changes of which matter is
susceptible, and as these never afford us any idea of thought or
perception, 'tis concluded to be impossible, that thought can ever
be caused by matter.
"Few have been able to withstand the seeming evidence of this
argument; and yet nothing in the world is more easy than to refute
it. We need only reflect upon what has been proved at large, that
we are never sensible of any connexion between causes and effects,
and that 'tis only by our experience of their constant conjunction
we can arrive at any knowledge of this relation. Now, as all
objects which are not contrary are susceptible of a constant
conjunction, and as no real objects are contrary, I have inferred
from these principles (Part III. § 15) that, to consider the matter
_a priori_, anything may produce anything, and that we shall never
discover a reason why any object may or may not be the cause of any
other, however great, or however little, the resemblance may be
betwixt them. This evidently destroys the precedent reasoning,
concerning the cause of thought or perception. For though there
appear no manner of connection betwixt motion and thought, the case
is the same with all other causes and effects. Place one body of a
pound weight on one end of a lever, and another body of the same
weight on the other end; you will never find in these bodies any
principle of motion dependent on their distance from the centre,
more than of thought and perception. If you pretend, therefore, to
prove, _a priori_, that such a position of bodies can never cause
thought, because, turn it which way you will, it is nothing but a
position of bodies: you must, by the same course of reasoning,
conclude that it can never produce motion, since there is no more
apparent connection in the one than in the other. But, as this
latter conclusion is contrary to evident experience, and as 'tis
possible we may have a like experience in the operations of the
mind, and may perceive a constant conjunction of thought and
motion, you reason too hastily when, from the mere consideration of
the ideas, you conclude that 'tis impossible motion can ever
produce thought, or a different position of parts give rise to a
different passion or reflection. Nay, 'tis not only possible we may
have such an experience, but 'tis certain we have it; since every
one may perceive that the different dispositions of his body change
his thoughts and sentiments. And should it be said that this
depends on the union of soul and body, I would answer, that we must
separate the question concerning the substance of the mind from
that concerning the cause of its thought; and that, confining
ourselves to the latter question, we find, by the comparing their
ideas, that thought and motion are different from each other and by
experience, that they are constantly united; which, being all the
circumstances that enter into the idea of cause and effect, when
applied to the operations of matter, we may certainly conclude that
motion may be, and actually is, the cause of thought and
perception."--(I. pp. 314-316.)
The upshot of all this is, that the "collection of perceptions," which
constitutes the mind, is really a system of effects, the causes of which
are to be sought in antecedent changes of the matter of the brain, just
as the "collection of motions," which we call flying, is a system of
effects, the causes of which are to be sought in the modes of motion of
the matter of the muscles of the wings.
Hume, however, treats of this important topic only incidentally. He
seems to have had very little acquaintance even with such physiology as
was current in his time. At least, the only passage of his works,
bearing on this subject, with which I am acquainted, contains nothing
but a very odd version of the physiological views of Descartes:--
"When I received the relations of _resemblance_, _contiguity_, and
_causation_, as principles of union among ideas, without examining
into their causes, 'twas more in prosecution of my first maxim,
that we must in the end rest contented with experience, than for
want of something specious and plausible which I might have
displayed on that subject. 'Twould have been easy to have made an
imaginary dissection of the brain, and have shown why, upon our
conception of any idea, the animal spirits run into all the
contiguous traces and rouse up the other ideas that are related to
it. But though I have neglected any advantage which I might have
drawn from this topic in explaining the relations of ideas, I am
afraid I must here have recourse to it, in order to account for the
mistakes that arise from these relations. I shall therefore
observe, that as the mind is endowed with the power of exciting any
idea it pleases; whenever it despatches the spirits into that
region of the brain in which the idea is placed; these spirits
always excite the idea, when they run precisely into the proper
traces and rummage that cell which belongs to the idea. But as
their motion is seldom direct, and naturally turns a little to the
one side or to the other; for this reason the animal spirits,
falling into the contiguous traces, present other related ideas, in
lieu of that which the mind desired at first to survey. This change
we are not always sensible of; but continuing still the same train
of thought, make use of the related idea which is presented to us
and employ it in our reasonings, as if it were the same with what
we demanded. This is the cause of many mistakes and sophisms in
philosophy; as will naturally be imagined, and as it would be easy
to show, if there was occasion."--(I. p. 88.)
Perhaps it is as well for Hume's fame that the occasion for further
physiological speculations of this sort did not arise. But, while
admitting the crudity of his notions and the strangeness of the language
in which they are couched, it must in justice be remembered, that what
are now known as the elements of the physiology of the nervous system
were hardly dreamed of in the first half of the eighteenth century; and,
as a further set off to Hume's credit, it must be noted that he grasped
the fundamental truth, that the key to the comprehension of mental
operations lies in the study of the molecular changes of the nervous
apparatus by which they are originated.
Surely no one who is cognisant of the facts of the case, nowadays,
doubts that the roots of psychology lie in the physiology of the nervous
system. What we call the operations of the mind are functions of the
brain, and the materials of consciousness are products of cerebral
activity. Cabanis may have made use of crude and misleading phraseology
when he said that the brain secretes thought as the liver secretes bile;
but the conception which that much-abused phrase embodies is,
nevertheless, far more consistent with fact than the popular notion that
the mind is a metaphysical entity seated in the head, but as independent
of the brain as a telegraph operator is of his instrument.
It is hardly necessary to point out that the doctrine just laid down is
what is commonly called materialism. In fact, I am not sure that the
adjective "crass," which appears to have a special charm for rhetorical
sciolists, would not be applied to it. But it is, nevertheless, true
that the doctrine contains nothing inconsistent with the purest
idealism. For, as Hume remarks (as indeed Descartes had observed long
before):--
"'Tis not our body we perceive when we regard our limbs and
members, but certain impressions which enter by the senses; so that
the ascribing a real and corporeal existence to these impressions,
or to their objects, is an act of the mind as difficult to explain
as that [the external existence of objects] which we examine at
present."--(I. p. 249.)
Therefore, if we analyse the proposition that all mental phenomena are
the effects or products of material phenomena, all that it means amounts
to this; that whenever those states of consciousness which we call
sensation, or emotion, or thought, come into existence, complete
investigation will show good reason for the belief that they are
preceded by those other phenomena of consciousness to which we give the
names of matter and motion. All material changes appear, in the long
run, to be modes of motion; but our knowledge of motion is nothing but
that of a change in the place and order of our sensations; just as our
knowledge of matter is restricted to those feelings of which we assume
it to be the cause.
It has already been pointed out, that Hume must have admitted, and in
fact does admit, the possibility that the mind is a Leibnitzian monad,
or a Fichtean world-generating Ego, the universe of things being merely
the picture produced by the evolution of the phenomena of consciousness.
For any demonstration that can be given to the contrary effect, the
"collection of perceptions" which makes up our consciousness may be an
orderly phantasmagoria generated by the Ego, unfolding its successive
scenes on the background of the abyss of nothingness; as a firework,
which is but cunningly arranged combustibles, grows from a spark into a
coruscation, and from a coruscation into figures, and words, and
cascades of devouring fire, and then vanishes into the darkness of the
night.
On the other hand, it must no less readily be allowed that, for anything
that can be proved to the contrary, there may be a real something which
is the cause of all our impressions; that sensations, though not
likenesses, are symbols of that something; and that the part of that
something, which we call the nervous system, is an apparatus for
supplying us with a sort of algebra of fact, based on those symbols. A
brain may be the machinery by which the material universe becomes
conscious of itself. But it is important to notice that, even if this
conception of the universe and of the relation of consciousness to its
other components should be true, we should, nevertheless, be still bound
by the limits of thought, still unable to refute the arguments of pure
idealism. The more completely the materialistic position is admitted,
the easier is it to show that the idealistic position is unassailable,
if the idealist confines himself within the limits of positive
knowledge.
Hume deals with the questions whether all our ideas are derived from
experience, or whether, on the contrary, more or fewer of them are
innate, which so much exercised the mind of Locke, after a somewhat
summary fashion, in a note to the second section of the _Inquiry_:--
"It is probable that no more was meant by those who denied innate
ideas, than that all ideas were copies of our impressions; though
it must be confessed that the terms which they employed were not
chosen with such caution, nor so exactly defined, as to prevent all
mistakes about their doctrine. For what is meant by _innate_? If
innate be equivalent to natural, then all the perceptions and ideas
of the mind must be allowed to be innate or natural, in whatever
sense we take the latter word, whether in opposition to what is
uncommon, artificial, or miraculous. If by innate be meant
contemporary with our birth, the dispute seems to be frivolous; nor
is it worth while to inquire at what time thinking begins, whether
before, at, or after our birth. Again, the word _idea_ seems to be
commonly taken in a very loose sense by Locke and others, as
standing for any of our perceptions, our sensations and passions,
as well as thoughts. Now in this sense I should desire to know what
can be meant by asserting that self-love, or resentment of
injuries, or the passion between the sexes is not innate?
"But admitting these terms, _impressions_ and _ideas_, in the
sense above explained, and understanding by _innate_ what is
original or copied from no precedent perception, then we may assert
that all our impressions are innate, and our ideas not innate."
It would seem that Hume did not think it worth while to acquire a
comprehension of the real points at issue in the controversy which he
thus carelessly dismisses.
Yet Descartes has defined what he means by innate ideas with so much
precision, that misconception ought to have been impossible. He says
that, when he speaks of an idea being "innate," he means that it exists
potentially in the mind, before it is actually called into existence by
whatever is its appropriate exciting cause.
"I have never either thought or said," he writes, "that the mind
has any need of innate ideas [_idées naturelles_] which are
anything distinct from its faculty of thinking. But it is true that
observing that there are certain thoughts which arise neither from
external objects nor from the determination of my will, but only
from my faculty of thinking; in order to mark the difference
between the ideas or the notions which are the forms of these
thoughts, and to distinguish them from the others, which may be
called extraneous or voluntary, I have called them innate. But I
have used this term in the same sense as when we say that
generosity is innate in certain families; or that certain maladies,
such as gout or gravel, are innate in others; not that children
born in these families are troubled with such diseases in their
mother's womb; but because they are born with the disposition or
the faculty of contracting them."[22]
His troublesome disciple, Regius, having asserted that all our ideas
come from observation or tradition, Descartes remarks:--
"So thoroughly erroneous is this assertion, that whoever has a
proper comprehension of the action of our senses, and understands
precisely the nature of that which is transmitted by them to our
thinking faculty, will rather affirm that no ideas of things, such
as are formed in thought, are brought to us by the senses, so that
there is nothing in our ideas which is other than innate in the
mind (_naturel à l'esprit_), or in the faculty of thinking, if only
certain circumstances are excepted, which belong only to
experience. For example, it is experience alone which causes us to
judge that such and such ideas, now present in our minds, are
related to certain things which are external to us; not in truth,
that they have been sent into our mind by these things, such as
they are, by the organs of the senses; but because these organs
have transmitted something which has occasioned the mind, in virtue
of its innate power, to form them at this time rather than at
another....
"Nothing passes from external objects to the soul except certain
motions of matter (_mouvemens corporels_), but neither these
motions, nor the figures which they produce, are conceived by us as
they exist in the sensory organs, as I have fully explained in my
"Dioptrics"; whence it follows that even the ideas of motion and of
figures are innate (_naturellement en nous_). And, _à fortiori_,
the ideas of pain, of colours, of sounds, and of all similar things
must be innate, in order that the mind may represent them to
itself, on the occasion of certain motions of matter with which
they have no resemblance."
Whoever denies what is, in fact, an inconceivable proposition, that
sensations pass, as such, from the external world into the mind, must
admit the conclusion here laid down by Descartes, that, strictly
speaking, sensations, and _à fortiori_, all the other contents of the
mind, are innate. Or, to state the matter in accordance with the views
previously expounded, that they are products of the inherent properties
of the thinking organ, in which they lie potentially, before they are
called into existence by their appropriate causes.
But if all the contents of the mind are innate, what is meant by
experience?
It is the conversion, by unknown causes, of these innate potentialities
into actual existences. The organ of thought, prior to experience, may
be compared to an untouched piano, in which it may be properly said that
music is innate, inasmuch as its mechanism contains, potentially, so
many octaves of musical notes. The unknown cause of sensation which
Descartes calls the "je ne sais quoi dans les objets" or "choses telles
qu'elles sont," and Kant the "Noumenon" or "Ding an sich," is
represented by the musician; who, by touching the keys, converts the
potentiality of the mechanism into actual sounds. A note so produced is
the equivalent of a single experience.
All the melodies and harmonies that proceed from the piano depend upon
the action of the musician upon the keys. There is no internal mechanism
which, when certain keys are struck, gives rise to an accompaniment of
which the musician is only indirectly the cause. According to Descartes,
however--and this is what is generally fixed upon as the essence of his
doctrine of innate ideas--the mind possesses such an internal mechanism,
by which certain classes of thoughts are generated, on the occasion of
certain experiences. Such thoughts are innate, just as sensations are
innate; they are not copies of sensations, any more than sensations are
copies of motions; they are invariably generated in the mind, when
certain experiences arise in it, just as sensations are invariably
generated when certain bodily motions take place; they are universal,
inasmuch as they arise under the same conditions in all men; they are
necessary, because their genesis under these conditions is invariable.
These innate thoughts are what Descartes terms "vérités" or truths: that
is beliefs--and his notions respecting them are plainly set forth in a
passage of the _Principes_.
"Thus far I have discussed that which we know as things: it remains
that I should speak of that which we know as truths. For example,
when we think that it is impossible to make anything out of
nothing, we do not imagine that this proposition is a thing which
exists, or a property of something, but we take it for a certain
eternal truth, which has its seat in the mind (_pensée_), and is
called a common notion or an axiom. Similarly, when we affirm that
it is impossible that one and the same thing should exist and not
exist at the same time; that that which has been created should not
have been created; that he who thinks must exist while he thinks;
and a number of other like propositions; these are only truths, and
not things which exist outside our thoughts. And there is such a
number of these that it would be wearisome to enumerate them: nor
is it necessary to do so, because we cannot fail to know them when
the occasion of thinking about them presents itself, and we are not
blinded by any prejudices."
It would appear that Locke was not more familiar with Descartes'
writings than Hume seems to have been; for, viewed in relation to the
passages just cited, the arguments adduced in his famous polemic against
innate ideas are totally irrelevant.
It has been shown that Hume practically, if not in so many words,
admits the justice of Descartes' assertion that, strictly speaking,
sensations are innate; that is to say, that they are the product of the
reaction of the organ of the mind on the stimulus of an "unknown cause,"
which is Descartes' "je ne sais quoi." Therefore, the difference between
Descartes' opinion and that of Hume resolves itself into this: Given
sensation-experiences, can all the contents of consciousness be derived
from the collocation and metamorphosis of these experiences? Or, are new
elements of consciousness, products of an innate potentiality distinct
from sensibility, added to these? Hume affirms the former position,
Descartes the latter. If the analysis of the phenomena of consciousness
given in the preceding pages is correct, Hume is in error; while the
father of modern philosophy had a truer insight, though he overstated
the case. For want of sufficiently searching psychological
investigations, Descartes was led to suppose that innumerable ideas, the
evolution of which in the course of experience can be demonstrated, were
direct or innate products of the thinking faculty.
As has been already pointed out, it is the great merit of Kant that he
started afresh on the track indicated by Descartes, and steadily upheld
the doctrine of the existence of elements of consciousness, which are
neither sense-experiences nor any modifications of them. We may demur to
the expression that space and time are forms of sensory intuition; but
it imperfectly represents the great fact that co-existence and
succession are mental phenomena not given in the mere sense
experience.[23]
FOOTNOTES:
[22] Remarques de René Descartes sur un certain placard imprimé aux Pays
Bas vers la fin de l'année, 1647.--Descartes, _OEuvres_. Ed. Cousin,
x. p. 71.
[23] "Wir können uns keinen Gegenstand denken, ohne durch Kategorien;
wir können keinen gedachten Gegenstand erkennen, ohne durch
Anschauungen, die jenen Begriffen entsprechen. Nun sind alle unsere
Anschauungen sinnlich, und diese Erkenntniss, so fern der Gegenstand
derselben gegeben ist, ist empirisch. Empirische Erkenntniss aber ist
Erfahrung. Folglich ist uns keine Erkenntniss _a priori_ möglich, als
lediglich von Gegenständen möglicher Erfahrung."
"Aber diese Erkenntniss, die bloss auf Gegenstände der Erfahrung
eingeschränkt ist, ist darum nicht alle von der Erfahrung entlehnt,
sondern was sowohl die reinen Anschauungen, als die reinen
Verstandesbegriffe betrifft, so sind sie Elemente der Erkenntniss die in
uns _a priori_ angetroffen werden."--_Kritik der reinen Vernunft.
Elementarlehre_, p. 135.
Without a glossary explanatory of Kant's terminology, this passage would
be hardly intelligible in a translation; but it may be paraphrased thus:
All knowledge is founded upon experiences of sensation, but it is not
all derived from those experiences; inasmuch as the impressions of
relation ("reine Anschauungen"; "reine Verstandesbegriffe") have a
potential or _à priori_ existence in us, and by their addition to
sense-experiences, constitute knowledge.