If, on the other hand, the claim is that these

prin-
222 Chapter 8
ciples, then it is clearly false. If, on the other hand, the claim is that these
are the principles of a theory that a self-conscious subject must tacitly
know, then the claim seems very uninformative in the absence of a specification
of the precise forms of behavior that can only be explained
by the ascription of such a body of tacit knowledge. We need an account
of what it is for a subject to be correctly described as possessing such a
simple theory of perception. My own view is that some of the navigational
abilities discussed in this chapter will have a central role to play in
this account. But there is no need for present purposes to make a claim
that strong. The point I wish to stress is simply that the notion of a nonconceptual
point of view as I have presented it can be viewed as capturing,
at a more primitive level, precisely the same phenomenon that Evans is
trying to capture with his notion of a simple theory of perception.
There is an important respect, though, in which Evans’s emphasis on a
simple theory of perception can be misleading. Although usefully highlighting
the spatiality of the self-conscious subject, it focuses attention on
the passive “input” side of that spatiality, rather than the active “output”
side. A vital element in a self-conscious subject’s grasp of how he himself
is a part of the physical world is indeed derived from an understanding of
how his perceptions are a function of his location in precisely the way
that Evans brings out. But it must not be forgotten that a vital role in this
is played by the subject’s own actions and movement. Appreciating the
spatiality of the environment and one’s place in it is largely a function of
grasping one’s possibilities for action within that environment: realizing
that if one wants to return to a particular place from here one must pass
through these intermediate places, or that if there is something there that
one wants, one should take this route to obtain it. That this is something
that Evans’s account could potentially overlook emerges when one reflects
that a simple theory of perception of the form that he describes could be
possessed and deployed by a subject that only moves passively. I take it to
be an advantage of the notion sketched in this chapter that it incorporates
the dimension of action by emphasizing the practicalities of navigation.
Moreover, stressing the importance of action and movement indicates
how the notion of a nonconceptual point of view might be grounded in
the self-specifying information to be found in visual perception. I am
thinking here particularly of the concept of an affordance so central to
Navigation and Spatial Reasoning 223
Gibsonian theories of perception. One important type of self-specifying
information in the visual field is information about the possibilities for
action and reaction that the environment affords the perceiver, and I suggested
earlier (in chapter 5) that affordances are nonconceptual firstperson
contents that serve as building blocks in the development of selfconsciousness
(though there are certain qualifications that emerged in
chapter 7 that have to do with the importance of conscious memory). We
are now in a position to give this idea a little more focus (albeit programmatically).
The development of a nonconceptual point of view clearly involves
certain forms of reasoning, which I earlier followed Peacocke in
calling spatial reasoning. Clearly, we will not have a full understanding
of the notion of a nonconceptual point of view until we have an explanation
of how this reasoning can take place. What I would suggest, though,
is that Gibsonian affordances form one important class of representations
over which this reasoning takes place. The spatial reasoning involved in
developing a nonconceptual point of view upon the world is largely a
matter of calibrating different affordances into an integrated representation
of the world. This idea obviously needs to be worked out in detail,
but let me make some brief comments about what might be involved in
such a process of calibration and how it relates to discussion earlier in
this chapter.
Calibrating different affordances into an integrated representation of
the world will be a function of a creature’s understanding how those affordances
are spatially related to each other, and the basic materials for
such a calibration will, of course, be the navigational abilities involved in
getting from one affordance to another. Let me give some examples of
what might be involved here. I will assume that when a creature is able
to navigate from one affordance to another in a way that satisfies the two
minimal conditions discussed earlier, it is appropriate to describe it as
having an understanding of the spatial relation between those affordances.
The question is how an understanding of individual spatial relations
of that sort becomes an integrated representation of the environment.
One very basic point here is that the spatial relations holding between
affordances have the properties of symmetry and transitivity. Correspondingly,
calibrating affordances involves recognizing such symmetry and
transitivity. Let me term this a grasp of affordance symmetry and af-
224 Chapter 8
fordance transitivity. If a particular route R leads from affordance A to
affordance A9, then a creature who has grasped affordance symmetry will
recognize that reversing the route will take him from affordance A9 to
affordance A. By the same token, a creature who has grasped affordance
transitivity will recognize that if route R leads from affordance A to affordance
A9 and route R9 leads from affordance A9 to affordance A0, then
R followed by R9 will take him from A to A0, and so on for any combination
of connected routes.
At a more sophisticated level, consider the following. Calibrating affordances
into an integrated representation of the world will involve the
capacity to distinguish affordances from the places at which those affordances
hold, and vice versa. A grasp of what I would term affordance
identities is one fundamental component of this capacity. Grasping affordance
identities is grasping that a given place can have different affordances
over time and, correlatively, that a different affordance does
not necessarily mean a different place. Understanding affordance identities
will involve, for example, understanding that the spatial relations
holding between a given affordance A at a particular place P and other
affordances A9, A0, . . . at other places P9, P0, . . . will continue to hold
even if A intermittently ceases to hold at P and is replaced by A*. More
concretely, suppose that an animal lives near a watering hole, from which
it is safe to drink at all times of day except early morning and dusk when
it is visited by predators. Here we have a place P (the watering hole) with
two different affordances: A (water) and A* (serious danger). A creature
who has grasped the identity of A and A* will understand that the spatial
relations that hold between A and other affordances A9, A0, . . . at P9, P0,
. . . hold equally between A* and those other affordances. For example,
suppose the creature is familiar with the route from a particular tree to
the watering hole and usually visits the watering hole after visiting the
tree. If the creature has grasped the affordance identity of A and A*, it
will know not to take that route at dawn or dusk.
Suppose that a creature moves towards an integrated representation of
its environment by applying its understanding of affordance symmetry,
affordance transitivity, and affordance identity to its understanding of
the spatial relations holding between individual affordances. When does
the process end? When would it be right to say that the creature has an