Is Visual Space Euclidean?

Abstract

Philosophers of past times have claimed that the answer to the question, Is visual space Euclidean?, can be answered by a priori or purely philo­sophical methods. Today such a view is presumably held only in remote philosophical backwaters. It would be generally agreed that one way or another the answer is surely empirical, but the answer might be empirical for indirect reasons. It could be decided by physical arguments that physi­cal space is Euclidean and then by conceptual arguments about perception that necessarily the visual space must be Euclidean. To some extent this must be the view of many laymen who accept that to a high degree of approximation physical space is Euclidean, and therefore automatically hold the view that visual space is Euclidean.