Abstract:
This thesis explores the debate and issues regarding the status of visual ;,iferellces
in the optical writings of Rene Descartes, George Berkeley and James 1. Gibson. It
gathers arguments from across their works and synthesizes an account of visual depthperception
that accurately reflects the larger, metaphysical implications of their
philosophical theories. Chapters 1 and 2 address the Cartesian and Berkelean theories of
depth-perception, respectively. For Descartes and Berkeley the debate can be put in the
following way: How is it possible that we experience objects as appearing outside of us,
at various distances, if objects appear inside of us, in the representations of the
individual's mind? Thus, the Descartes-Berkeley component of the debate takes place
exclusively within a representationalist setting. Representational theories of depthperception
are rooted in the scientific discovery that objects project a merely twodimensional
patchwork of forms on the retina. I call this the "flat image" problem. This
poses the problem of depth in terms of a difference between two- and three-dimensional
orders (i.e., a gap to be bridged by one inferential procedure or another). Chapter 3
addresses Gibson's ecological response to the debate. Gibson argues that the perceiver
cannot be flattened out into a passive, two-dimensional sensory surface. Perception is
possible precisely because the body and the environment already have depth.
Accordingly, the problem cannot be reduced to a gap between two- and threedimensional
givens, a gap crossed with a projective geometry. The crucial difference is
not one of a dimensional degree. Chapter 3 explores this theme and attempts to excavate
the empirical and philosophical suppositions that lead Descartes and Berkeley to their
respective theories of indirect perception. Gibson argues that the notion of visual
inference, which is necessary to substantiate representational theories of indirect
perception, is highly problematic. To elucidate this point, the thesis steps into the
representationalist tradition, in order to show that problems that arise within it demand a
tum toward Gibson's information-based doctrine of ecological specificity (which is to
say, the theory of direct perception). Chapter 3 concludes with a careful examination of
Gibsonian affordallces as the sole objects of direct perceptual experience. The final
section provides an account of affordances that locates the moving, perceiving body at
the heart of the experience of depth; an experience which emerges in the dynamical
structures that cross the body and the world.
