Conference | Paper

The term “perceptual constancy” (or “object constancy”) denotes the fact that we see familiar objects as having a fixed shape, size, color, or location despite changes in the angle of perspective, distance, or lighting.
Using perceptual constancy as a platform, in the first part of the talk I discuss the difficulties that arise when an attempt is made to capture geometrically the effect of perspective change on perception. I argue that our grasp of shapes is independent of our success in this endeavor, or, to put it differently, that failure to mathematically represent aspects of experience is not necessarily indicative of weaknesses in our phenomenology.
In the second part of the talk I suggest that the phenomenon of perceptual constancy can also be found in relation to shapes of pure mathematics, such as shapes on the Euclidean plane. This requires expanding the notion of perspective so that it includes changes that are not spatial.
Both parts belong to a broader project aimed at establishing that to be a certain shape is to look that shape, a thesis which, I argue, holds equally for material/imagined shapes and to mathematical shapes.