II

Contemporary realists have so frequently and clearly expounded the

physical explanation of such cases as have been cited that one is at a

loss as to why idealists go on repeating the cases without even

alluding to the realistic explanation. One is moved to wonder whether

this neglect is just one of those circumstances which persistently dog

philosophical discussions, or whether something in the realistic

position gives ground (from at least an _ad hominem_ point of view)

for the neglect. There is a reason for adopting the latter

alternative. Many realists, in offering the type of explanation

adduced above, have treated the cases of seen light, doubled imagery,

as perception in a way that ascribes to perception an inherent

cognitive status. They have treated the perceptions as _cases of

knowledge_, instead of as simply natural events having, in themselves

(apart from a _use_ that may be made of them), no more knowledge

status or worth than, say, a shower or a fever. What I intend to show

is that if "perceptions" are regarded as cases of knowledge, the gate

is opened to the idealistic interpretation. The physical explanation

holds of them as long as they are regarded simply as natural events--a

doctrine I shall call naïve realism; it does not hold of them

considered as cases of knowledge--the view I call presentative

realism.

The idealists attribute to the realists the doctrine that "the

perceived object is the real object." Please note the wording; it

assumes that there is _the_ real object, something which stands in a

contrasting relation with objects not real or else less real. Since it

is easily demonstrable that there is a numerical duplicity between the

astronomical star and its effect of visible light, between the single

finger and the doubled images, the latter evidently, when the former

is dubbed "_the_" real object, stands in disparaging contrast to its

reality. _If_ it is a case of knowledge, the knowledge refers to the

star; and yet not the star, but something more or less unreal (that

is, if the star be "the" real object), is known.

Consider how simply the matter stands in what I have called naïve

realism. The astronomical star is _a_ real object, but not "the" real

object; the visible light is another real object, found, when

knowledge supervenes, to be an occurrence standing in a process

continuous with the star. Since the seen light is an event within a

continuous process, there is no point of view from which its

"reality" contrasts with that of the star.

But suppose that the realist accepts the traditionary psychology

according to which every event in the way of a perception is also a

case of knowing something. Is the way out now so simple? In the case

of the doubled fingers or the seen light, the thing known in

perception contrasts with the physical source and cause of the

knowledge. There _is_ a numerical duplicity. Moreover the thing known

by perception is by this hypothesis in relation to a knower, while the

physical cause is not. Is not the most plausible account of the

difference between the physical cause of the perceptive knowledge and

what the latter presents precisely this latter difference--namely,

presentation to a knower? If perception is a case of knowing, it must

be a case of knowing the star; but since the "real" star is not known

in the perception, the knowledge relation must somehow have changed

the "object" into a "content." Thus when the realist conceives the

perceptual occurrence as an intrinsic case of knowledge or of

presentation to a mind or knower, he lets the nose of the idealist

camel into the tent. He has then no great cause for surprise when the

camel comes in--and devours the tent.

Perhaps it will seem as if in this last paragraph I had gone back on

what I said earlier regarding the physical explanation of the

difference between the visible light and the astronomical star. On

the contrary, my point is that this explanation, though wholly

adequate as long as we conceive the perception to be itself simply a

natural event, is not at all available when we conceive it to be an

attempt at knowing its cause. In the former case, we are dealing with

a relation between natural events. In the latter case, we are dealing

with the difference between an object as a cause of knowledge and an

object as known, and hence in relation to mind. By the "method of

difference" the sole explanation of the difference between the two

objects is then the absence or presence of relation to a knower.

In the case of the seen light,[60] reference to the velocity of light

is quite adequate to account for its time and space differences from

the star. But viewed as a case of what is known (on the supposition

that perception is knowing), reference to it only increases the

contrast between the real object and the object known in perception.

For, being just as much a part of the object that causes the

perception as is the star itself, it (the velocity of light) _ought_

logically to be part of what is known in the perception, while it is

not. Since the velocity of light is a constituent element in the

star, it should be known in the perception; since it is not so known,

reference to it only increases the discrepancy between the object of

the perception--the seen light--and the real, astronomical star. The

same is true of any physical condition that might be referred to: _The

very things that, from the standpoint of perception as a natural

event, are conditions that account for its happening are, from the

standpoint of perception as a case of knowledge, part of the object

which, if knowledge is to be valid, ought to be known, but is not._

In this fact we have, perhaps, the ground of the idealist's disregard

of the oft-proffered physical explanation of the difference between

the perceptual event and _the_ (so-called) real object. And it is

quite possible that some realists who read these lines will feel that

in my last paragraphs I have been making a covert argument for

idealism. Not so, I repeat; they are an argument for a truly naïve

realism. The presentative realist, in his appeal to "common-sense" and

the "plain man," first sophisticates the umpire and then appeals. He

stops a good way short of a genuine naïveté. The plain man, for a

surety, does not regard noises heard, lights seen, etc., as mental

existences; but neither does he regard them as things _known_. That

they are just things is good enough for him. That they are in relation

to mind, or in relation to mind as their "knower," no more occurs to

him than that they are mental. By this I mean much more than that the

formulae of epistemology are foreign to him; I mean that his attitude

to these things _as_ things involves their _not_ being in relation to

him as a mind or a knower. He is in the attitude of a liker or hater,

a doer or an appreciator. When he takes the attitude of a knower he

begins to inquire. Once depart from thorough naïveté, and substitute

for it the psychological theory that perception is a cognitive

presentation to a mind of a causal object, and the first step is taken

on the road which ends in an idealistic system.