PERCEPTION.

We have now to examine Kant s teaching on the

validity of sense perception, culminating as it docs in the view

that space and time are not features or characteristics of what is

given in sense perception, but are a priori mental endowments,

pure forms of sensibility, which render sense perception possible.

If it is true that Kant never relinquished his hold on extramental

reality, it is equally true that he kept his hold on it in defiance

of the whole theory outlined in the Critique of Pure Reason.

Many of the positions adopted in the course of the Critique are

untenable, 1 if not indeed meaningless,- unless on the assumption

that at least in sense perception the mind is directly aware of

extramental reality, an assumption that is fundamentally op

posed to the main assumption underlying the Critique.

We do not consider that Kant is to be blamed for not having

avowedly presupposed the validity of man s spontaneous convic

tion that the mind can know reality as it is, and conducted his

analysis in the light of this presupposition, though de facto it is

really latent in the opening passages of the Critique, where he

says that "by the sensibility objects are given to us," 3 where he

speaks of " objects which affect our senses," 4 and where he speaks

of reality in the plural as "things in themselves," seemingly

identifying these with real bodies in space. But we do think

that he adopted an unjustifiable procedure by introducing tacitly

at an early stage of his inquiry the opposite assumption, viz. that

the mind cannot know reality as it is, t; and by allowing this as-

1 E.g. the supposition that only a priori judgments, and not a posteriori judg

ments give rise to any "problem of knowledge" (cf. % 55 ; PRICHARD, op. cit.,

pp. 3 7 66-8).

E.g. the supposition that the cause of sensation is "a spatial and temporal

world " of " physical bodies," and that " this world is what we come to know".

PRICHARD, p. 32.

3 Critique, p. 40. *Ibid., p. 715.

Cf. PRICHARD, op. cit., pp. 30, 32. K Ibid., p. 30.

184

KANTS THEORY OF SENSE PERCEPTION, ETC. 185

sumption, perhaps unconsciously but none the less effectively,

to bias his whole analysis of our cognitive functions and their

a priori mental conditions, and indeed so to bias this analysis

that it inevitably issues in subjectivism.

That in the earlier portion of the Critique Kant vacillates

between the realist and the idealist views of sense perception

will be apparent from a comparison of the opening passages of

the Introduction (47) and the Transcendental Aesthetic (50> with

his subsequent treatment of the general problem of knowledge.

He commences by asserting that in intuition or perception, and

there alone, cognition directly reaches its " objects " ; that in

perception these act upon our sensibility and produce sensations

therein; that thereby objects are "given to us": "The effect

produced by an object upon the faculty of representation, so far

as we are affected by it, is called sensation. An intuition of an

object by means of a sensation is called empirical" (51). Now

here he identifies the "objects " with the " causes " of sensation,

and he is manifestly thinking of these as things and events in the

physical universe of space and time, for his aim is to explain our

sense knowledge of this latter. But as the sensation is in the

mind and the supposed cause or causes of it beyond and outside

the mind, and as he cannot see how anything extramental can be

presented to the mind or become an object of the mind s aware

ness, 1 he rejects the view that the causes of our sensations are

bodies and events in the physical universe, substituting the as

sumption that they are an unknowable reality ; 2 and he leaves us

1 In other words, how the mind can " transcend itself" (21). In one remarkable

passage of the Prolegomena Kant admits that it is at all events possible, if not posi

tively intelligible, that a thing present to perception can reveal itself as it is in itself.

" Were our perception necessarily of such a kind as to represent things as they are

in themselves, no perception would take place a priori, but would always be empiri

cal. For I can only know what is contained in the object in itself, if it is present

and given to me. No doubt it is even then unintelligible how the perception of a

present thing should make me know it as it is in itself, since its qualities cannot

migrate over into my faculty of representation ; but even granting this possibility

[italics ours], such a perception would not occur a priori, i.e. before the object was

presented tome. ..." (Prol.,g; cf. PRICHARD, op. cit., p. 55). If the "thing"

is " present " to " my faculty of representation," why should the " qualities " of the

thing have to " migrate over into " the latter, in order that the thing be known as it

is in itself? The notion that such " migration " is necessary reveals a rather crude

and mechanical conception of the process of cognition ; nor is it easy to see how

the mystery or obscurity of the latter is one whit lessened by supposing any sort

of real identity of the perceiver and the perceived (cf. 21).

2 Kant s employment of the principle; of causality here, to infer a transcendental

reality correlative to our sensations, is manifestly inconsistent with his own theory

as to the limits of its valid and legitimate employment.

1 86 THEOR Y OF KNO W LEDGE

wondering what " objects are given to us by the sensibility ".

What is given is simply a. manifold of sensations, a " raw material

of ... sensuous impressions " l (47), whereby we are to become

aware of a physical universe of bodies and events in space and

time. How this can be done is now the problem.

" For if [writes Prichard] the contribution of the sensibility to our

knowledge of the physical world is limited to a succession of sensations,

explanation must be given of the fact that we have succeeded with an experi

ence confined to sensations in acquiring a knowledge of a world which does

not consist of sensations. Kant, in fact, in the Aesthetic has this problem

continually before him, and tries to solve it. He holds that the mind . . .

superinduces upon sensations, as data, spatial and other relations in such a

way that it acquires knowledge of the spatial world." "

In stating the problem Kant appears to have been un

doubtedly influenced by his assumption of realism, i.e. the spon

taneous conviction of mankind that our sensations are caused by

(extramental) bodies in space. And even after he had rejected

this assumption and ascribed the origin of sensations to extra-

mental, unknowable " things in themselves," he continued to

speak of these latter in terms which show that he was really think

ing of bodies in space. In corroboration of this, Prichard refers

to " certain passages in the Critique which definitely mention the

senses/ a term which refers to bodily organs," and to " others to

which meaning can be given only if they are taken to imply that

the objects which affect our sensibility are not unknown things in

themselves, but things known to be spatial. Even the use of

the plural in the term things in themselves implies a tendency

to identify the unknowable reality beyond the mind with bodies

in space. For the implication that different sensations are due

to different things in themselves originates in the view that

different sensations are due to the operation of different spatial

bodies." 3

Prichard even contends that the problem of the Aesthetic,

" How do we, beginning with mere sensation, come to know a

spatial and temporal world?" is only a problem "so long as it

is supposed that the cause of sensation is a spatial and temporal

world or part of it, and that this world is what we come to know.

If the cause of sensation, as being beyond the mind, is held to

be unknowable and so not known to be spatial or temporal, the

1 Critique, p. 715. 2 Of. cit., p. 31. s lbid., p. 32,

KANTS THEORY OF SENSE PERCEPTION, ETC. 187

problem has disappeared." l We would say rather, that the prob

lem is changed. It is now no longer the (insoluble) problem,

" How do we, beginning with mere awareness of our own indivi

dual mental states, originated by a supposed extramental reality,

ever come to know this latter ? " It is now the (fictitious) problem,

" How do we transform a chaotic stream of isolated sensuous im

pressions (originated in us by an unknowable reality) into the

orderly system of mental appearances which we apprehend as the

physical, material universe of space and time, and which, be it

remarked incidentally, uncritical people by a spontaneous illu

sion believe to be extramental?" His solution of this problem

(51) is that, whereas the visual, tactual, auditory, gustatory, and

olfactory elements (i.e. what are called the " proper sensibles " or

the " secondary qualities " of bodies) in our states of sense con

sciousness constitute the matter or data or chaotic manifold of

sense impressions, the space and time elements in these states (the

" common sensibles" or "primary qualities ") are not given em

pirically, with or in those sensation manifolds, but are pure

mental forms of a priori intuition ; and that only by the a priori

synthesis of these with the empirical data is it possible for us

to become conscious or aware of anything as a phenomenon of

physical nature existing in space and time. 2 We shall now deal

separately and in order with his attempts to prove space and

time to be a priori forms of sense perception.

We have now to examine Kant s teaching on the

validity of sense perception, culminating as it docs in the view

that space and time are not features or characteristics of what is

given in sense perception, but are a priori mental endowments,

pure forms of sensibility, which render sense perception possible.

If it is true that Kant never relinquished his hold on extramental

reality, it is equally true that he kept his hold on it in defiance

of the whole theory outlined in the Critique of Pure Reason.

Many of the positions adopted in the course of the Critique are

untenable, 1 if not indeed meaningless,- unless on the assumption

that at least in sense perception the mind is directly aware of

extramental reality, an assumption that is fundamentally op

posed to the main assumption underlying the Critique.

We do not consider that Kant is to be blamed for not having

avowedly presupposed the validity of man s spontaneous convic

tion that the mind can know reality as it is, and conducted his

analysis in the light of this presupposition, though de facto it is

really latent in the opening passages of the Critique, where he

says that "by the sensibility objects are given to us," 3 where he

speaks of " objects which affect our senses," 4 and where he speaks

of reality in the plural as "things in themselves," seemingly

identifying these with real bodies in space. But we do think

that he adopted an unjustifiable procedure by introducing tacitly

at an early stage of his inquiry the opposite assumption, viz. that

the mind cannot know reality as it is, t; and by allowing this as-

1 E.g. the supposition that only a priori judgments, and not a posteriori judg

ments give rise to any "problem of knowledge" (cf. % 55 ; PRICHARD, op. cit.,

pp. 3 7 66-8).

E.g. the supposition that the cause of sensation is "a spatial and temporal

world " of " physical bodies," and that " this world is what we come to know".

PRICHARD, p. 32.

3 Critique, p. 40. *Ibid., p. 715.

Cf. PRICHARD, op. cit., pp. 30, 32. K Ibid., p. 30.

184

KANTS THEORY OF SENSE PERCEPTION, ETC. 185

sumption, perhaps unconsciously but none the less effectively,

to bias his whole analysis of our cognitive functions and their

a priori mental conditions, and indeed so to bias this analysis

that it inevitably issues in subjectivism.

That in the earlier portion of the Critique Kant vacillates

between the realist and the idealist views of sense perception

will be apparent from a comparison of the opening passages of

the Introduction (47) and the Transcendental Aesthetic (50> with

his subsequent treatment of the general problem of knowledge.

He commences by asserting that in intuition or perception, and

there alone, cognition directly reaches its " objects " ; that in

perception these act upon our sensibility and produce sensations

therein; that thereby objects are "given to us": "The effect

produced by an object upon the faculty of representation, so far

as we are affected by it, is called sensation. An intuition of an

object by means of a sensation is called empirical" (51). Now

here he identifies the "objects " with the " causes " of sensation,

and he is manifestly thinking of these as things and events in the

physical universe of space and time, for his aim is to explain our

sense knowledge of this latter. But as the sensation is in the

mind and the supposed cause or causes of it beyond and outside

the mind, and as he cannot see how anything extramental can be

presented to the mind or become an object of the mind s aware

ness, 1 he rejects the view that the causes of our sensations are

bodies and events in the physical universe, substituting the as

sumption that they are an unknowable reality ; 2 and he leaves us

1 In other words, how the mind can " transcend itself" (21). In one remarkable

passage of the Prolegomena Kant admits that it is at all events possible, if not posi

tively intelligible, that a thing present to perception can reveal itself as it is in itself.

" Were our perception necessarily of such a kind as to represent things as they are

in themselves, no perception would take place a priori, but would always be empiri

cal. For I can only know what is contained in the object in itself, if it is present

and given to me. No doubt it is even then unintelligible how the perception of a

present thing should make me know it as it is in itself, since its qualities cannot

migrate over into my faculty of representation ; but even granting this possibility

[italics ours], such a perception would not occur a priori, i.e. before the object was

presented tome. ..." (Prol.,g; cf. PRICHARD, op. cit., p. 55). If the "thing"

is " present " to " my faculty of representation," why should the " qualities " of the

thing have to " migrate over into " the latter, in order that the thing be known as it

is in itself? The notion that such " migration " is necessary reveals a rather crude

and mechanical conception of the process of cognition ; nor is it easy to see how

the mystery or obscurity of the latter is one whit lessened by supposing any sort

of real identity of the perceiver and the perceived (cf. 21).

2 Kant s employment of the principle; of causality here, to infer a transcendental

reality correlative to our sensations, is manifestly inconsistent with his own theory

as to the limits of its valid and legitimate employment.

1 86 THEOR Y OF KNO W LEDGE

wondering what " objects are given to us by the sensibility ".

What is given is simply a. manifold of sensations, a " raw material

of ... sensuous impressions " l (47), whereby we are to become

aware of a physical universe of bodies and events in space and

time. How this can be done is now the problem.

" For if [writes Prichard] the contribution of the sensibility to our

knowledge of the physical world is limited to a succession of sensations,

explanation must be given of the fact that we have succeeded with an experi

ence confined to sensations in acquiring a knowledge of a world which does

not consist of sensations. Kant, in fact, in the Aesthetic has this problem

continually before him, and tries to solve it. He holds that the mind . . .

superinduces upon sensations, as data, spatial and other relations in such a

way that it acquires knowledge of the spatial world." "

In stating the problem Kant appears to have been un

doubtedly influenced by his assumption of realism, i.e. the spon

taneous conviction of mankind that our sensations are caused by

(extramental) bodies in space. And even after he had rejected

this assumption and ascribed the origin of sensations to extra-

mental, unknowable " things in themselves," he continued to

speak of these latter in terms which show that he was really think

ing of bodies in space. In corroboration of this, Prichard refers

to " certain passages in the Critique which definitely mention the

senses/ a term which refers to bodily organs," and to " others to

which meaning can be given only if they are taken to imply that

the objects which affect our sensibility are not unknown things in

themselves, but things known to be spatial. Even the use of

the plural in the term things in themselves implies a tendency

to identify the unknowable reality beyond the mind with bodies

in space. For the implication that different sensations are due

to different things in themselves originates in the view that

different sensations are due to the operation of different spatial

bodies." 3

Prichard even contends that the problem of the Aesthetic,

" How do we, beginning with mere sensation, come to know a

spatial and temporal world?" is only a problem "so long as it

is supposed that the cause of sensation is a spatial and temporal

world or part of it, and that this world is what we come to know.

If the cause of sensation, as being beyond the mind, is held to

be unknowable and so not known to be spatial or temporal, the

1 Critique, p. 715. 2 Of. cit., p. 31. s lbid., p. 32,

KANTS THEORY OF SENSE PERCEPTION, ETC. 187

problem has disappeared." l We would say rather, that the prob

lem is changed. It is now no longer the (insoluble) problem,

" How do we, beginning with mere awareness of our own indivi

dual mental states, originated by a supposed extramental reality,

ever come to know this latter ? " It is now the (fictitious) problem,

" How do we transform a chaotic stream of isolated sensuous im

pressions (originated in us by an unknowable reality) into the

orderly system of mental appearances which we apprehend as the

physical, material universe of space and time, and which, be it

remarked incidentally, uncritical people by a spontaneous illu

sion believe to be extramental?" His solution of this problem

(51) is that, whereas the visual, tactual, auditory, gustatory, and

olfactory elements (i.e. what are called the " proper sensibles " or

the " secondary qualities " of bodies) in our states of sense con

sciousness constitute the matter or data or chaotic manifold of

sense impressions, the space and time elements in these states (the

" common sensibles" or "primary qualities ") are not given em

pirically, with or in those sensation manifolds, but are pure

mental forms of a priori intuition ; and that only by the a priori

synthesis of these with the empirical data is it possible for us

to become conscious or aware of anything as a phenomenon of

physical nature existing in space and time. 2 We shall now deal

separately and in order with his attempts to prove space and

time to be a priori forms of sense perception.