For simplicity's sake, I have written as if my main problem were to
show how, in the face of a supposed difficulty, a strictly realistic
theory of the perceptual event may be maintained. But my interest is
primarily in the facts, and in the theory only because of the facts it
formulates. The significance of the facts of the case may, perhaps, be
indicated by a consideration which has thus far been ignored. In
regarding a perception as a case of knowledge, the presentative
realist does more than shove into it a relation to mind which then,
naturally and inevitably, becomes the explanation of any differences
that exist between its subject-matter and some causal object with
which it contrasts. In many cases--very important cases, too, in the
physical sciences--the contrasting "real object" becomes known by a
logical process, by inference--as the contemporary position of the
star is determined by calculations from data, not by perception. This,
then, is the situation of the presentative realist: If perception is
knowledge of its cause, it stands in unfavorable contrast with another
indirect mode of knowledge; _its_ object is less valid than the object
of inference. I do not adduce these considerations as showing that the
case is hopeless for the presentative realist;[61] I am willing to
concede he can find a satisfactory way out. But the difficulty exists;
and in existing it calls emphatic attention to a case which is
certainly and indisputably a case of knowledge--namely, propositions
arrived at through inference, judgments as logical assertions.
With relation to the unquestionable case of knowledge, the logical or
inferential case, perceptions occupy a unique status, one which
readily accounts for their being regarded as cases of knowledge,
although in themselves they are natural events. (1) They are the sole
ultimate data, the sole media, of inference to all natural objects and
processes. While we do not, in any intelligible or verifiable sense,
know _them_, we know all things that we do know _with_ or _by_ them.
They furnish the only ultimate evidence of the existence and nature
of the objects which we infer, and they are the sole ultimate checks
and tests of the inferences. The visible light is a necessary part of
the evidence on the basis of which we infer the existence, place, and
structure of the astronomical star, and some other perception is the
verifying check on the value of the inference. Because of this
characteristic use of perceptions, the perceptions themselves acquire,
by "second intention," a knowledge status. They _become_ objects of
minute, accurate, and experimental scrutiny. Since the body of
propositions that forms natural science hangs upon them, _for
scientific purposes_ their nature _as_ evidence, _as_ signs, entirely
overshadows their natural status, that of being simply natural events.
The scientific man, as scientific, cares for perceptions not in
themselves, but as they throw light upon the nature of some object
reached by evidence. And since every such inference tries to terminate
in a further perception (as its test of validity), the value of
inferential knowing depends on perception. (2) Independently of
science, daily life uses perceptions as signs of other perceptions.
When a perception of a certain kind frequently recurs and is
constantly used as evidence of some other impending perceptual event,
the function of habit (a natural function, be it noted, not a
psychical or epistemological function) often brings it about that the
perception loses its original quality in acquiring a sign-value.
Language is, of course, the typical case. Noises, in themselves mere
natural events, through habitual use as signs of other natural events
become integrated with what they mean. What they stand for is
telescoped, as it were, into what they are. This happens also with
other natural events, colors, tastes, etc. Thus, _for practical
purposes_, many perceptual events are cases of knowledge; that is,
they have been _used_ as such so often that the habit of so using them
is established or automatic.
In this brief reference to facts that are perfectly familiar, I have
tried to suggest three points of crucial importance for a naïve
realism: first, that inferential or evidential knowledge (that
involving logical relation) is in the field as an obvious and
undisputed case of knowledge; second, that this function, although
embodying the logical relation, is itself a natural and specifically
detectable process among natural things--it is not a non-natural or
epistemological relation; third, that the _use_, practical and
scientific, of perceptual events in the evidential or inferential
function is such as to make them _become_ objects of inquiry and
limits of knowledge, and to such a degree that this acquired
characteristic quite overshadows, in many cases, their primary nature.
If we add to what has been said the fact that, like every natural
function, the inferential function turns out better in some cases and
worse in others, we get a naturalistic or naïvely realistic conception
of the "_problem_ of knowledge": Control of the conditions of
inference--the only type of knowledge detectable in direct
existence--so as to guide it toward better conclusions.