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to things in the world; but some, indeed many, general concepts apply to things in the
world in virtue of properties not fully manifest to the senses, for example the concepts
of tiger or water. Such concepts hold of things in virtue of their 'inner constitution'--
being H2O or having a certain genetic structure. This means that it is possible for
things to have the same appearance as tigers and water yet not fall under the
concepts tiger and water; so there would be no phenomenological difference between
experiences whose content was specified using one of those concepts rather than
the concepts appropriate to the things that merely have the same appearance as
tigers and water. We should therefore restrict the concepts invoked to characterise
content to those that relate to the appearances of things--concepts of colour,
superficial texture, shape etc. In this way we limit our ascriptions of content to how
things seem to the perceiver.
The content of experience comprises the mode of perceptual presentation of the
object to the perceiver; it contains how the world is represented in experience, and so
the manner in which the mind apprehends the objects of perceptual acquaintance.
Our earlier conclusions can now be summarised in the thesis that perceptual modes
of presentation neither contain nor determine which object is thereby presented--the
singularity of the perceptual object is otherwise fixed.
Having clarified the structure of acts of perceptual acquaintance
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we can now address the following three questions: (a) What is the nature of the
dyadic relation of perceiving an object? (b) What determines the psychological
significance of an act of perceptual acquaintance? (c) How seriously should we take
talk of experiences representing objects?
We already know that the answer to question (a) cannot be that the object of
perception is the object which fits the content of the experience, since an object may
fit the general conditions comprised in the perceptual mode of presentation and yet
not be perceived, and the object perceived may fail to fit the content of the
experience. The missing ingredient seems to be a causal relation between the object
and the experience: it is a necessary condition of perceiving an object that the
experience be causally dependent on the object. Of course we know that, as a matter
of empirical fact, our perceptual experiences do depend upon a causal connection
with the object perceived; but it also seems evident enough that it is part of the
concept of perception that the dyadic perceptual relation is a species of causal
relation. The concept of memory is comparable in this respect: it is not conceptually
possible to remember an earlier event unless your memory of it is the end result of a
causal chain originating in the event in question. It is thus very plausible to construe
the relation of perception as a special case of the causal relation. To say this is not to
claim that we can fully analyse perception causally--in particular, it is not to say that
sufficient conditions for perception can be given in causal terms. In fact there seems
to be a very general and intractable difficulty in the way of achieving such an
analysis, which emerges when we consider certain kinds of non-standard causal
connections that may obtain between objects and experiences. Suppose you have an
experience as of an eye of such and such a character which you are caused to have
because of a malfunction in your own eye: then the fact that the experience was
caused by something precisely matching it, that is, the experience as of an eye was
caused by the eye, does not guarantee that you see your eye. What we have in this
case is a kind of accidental matching of content and object mediated by a causal
chain. It is probably impossible to specify in a non-circular manner what sorts of
causal chain make for genuine perception; but for our purposes it is not necessary to
claim that a full causal analysis is possible--it is enough to note that perception
necessarily involves a causal relation with the object, though of a kind not isolable
without using the notion of perception itself.
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This causal picture of the perception relation is confirmed by an important feature of
our concept of perception, namely that we distinguish between mediate and
immediate perceptual objects. We allow, that is, that one object may be perceived by
perceiving another, as when you see a cat by seeing its head. In general we allow
that objects may be seen in virtue of their parts--indeed surfaces of their parts--being
seen, rather as we allow that an object may be touched by touching its parts or their
surfaces. If we did not operate the concept of perception in this way we would, in a
sense, perceive much less than we do--we would see only parts or surfaces of things.
Conceiving perception as causal provides some sort of explanation for this, because
we similarly operate with a distinction between mediate and immediate causation: a
mediate cause of an event is one which causes it in virtue of some other cause, as
when we say a car caused a death by way of its bumper. We thus allow the causal
relation to be transmitted through the part-whole relation. So if we construe the
perception relation as a kind of causal relation, we can regard mediate and
immediate perceptual objects as corresponding to mediate and immediate causes;
and indeed it is plausible that we make judgements as to what is mediately perceived
on the basis of principles linking causation with part-whole relations.
A person's perception of the world clearly plays a role in his psychology: perception
gives rise to beliefs which interact with other elements of the mind to lead to
intelligent action. We may refer to this psychological role as the significance of an act
of perceptual acquaintance for the perceiver. Upon what does this significance
depend? It depends, evidently, upon how the world is represented as being, since
this is what functions as the basis of belief and thence action. The relational aspect of
perception, in contrast, has no such psychological significance, since it consists in
facts which are, in an obvious sense, outside the mind. Thus what affects behaviour
in perceptual situations is just how things seem to you. This can be appreciated by
considering cases of hallucination: if hallucinatory experiences are produced in you,
without your knowing them to be such, which exactly match veridical experiences in
their content, then you will behave just as you would were you in the perceptual
relation to objects. So when we explain why someone reached for a cup of coffee by
saying that he saw the cup this can be philosophically misleading in two ways: first, in [ Pobierz całość w formacie PDF ]