Abstract:
Some ecological psychologists understand direct perception in terms of (a) the detection of invariant properties of the medium, and (b) the existence of some ecological laws connecting such invariants to the to-be-perceived properties of the environment. For an organism O to perceive the environmental property e, O need only pick up or detect the invariant property nomically related to e. Call this the Nomic View. An alleged consequence of this view is that, if perception is direct in this lawful way, then perceptual knowledge is incorrigible—or, in other words, that there is no room for misperception. In this paper, we make a case against the Nomic View.
We will develop two lines of argument. The first line of objection has to do with the ‘exceptionless’ character of ecological laws. We will argue that ecological laws must make room for exceptions even within the niche, since such laws necessarily include a ceteris paribus clause that cannot be reduced to the individuating conditions of the niche. An initial implication is that misperception cannot be excluded and, therefore, the incorrigibility thesis will be challenged.
The second line of objection concerns the notions of invariant and specification. We argue that invariants cannot be individuated in such a way that they can serve as relata in ecological laws and specify the source of a medium property. We will thus conclude that, if there is a medium property that is to account for all the cases of perception of an environmental property (or, at least, a non-trivial subset of them), then this medium property cannot be a nomic property. Yet only nomic properties can be picked up or detected by an organism.