Online research in philosophy

Recent work in visual perception shows that its phenomenal and cognitive aspects cannot be distinguished sharply. A preferable treatment of visual perception is to describe perceptual strategies, which represent the various ways in which perceivers may focus interest, and which are treated in this paper by two examples. Perceptual strategies suggest that both Sense Data theories, on the one hand, and treatments of perception such as Hanson's, on the other, are over-simplified. This work further suggests that the traditional distinction between primary and secondary qualities should be replaced by an epistemological distinction between visual and physical qualities. Such a distinction clarifies epistemological investigations of perception and shows the relevance of experimental investigations of visual perception to epistemological problems.

What is difficult to imagine is also surprising to perceive. This indicates that active visual imagery is an integral part of active visual perception. Erroneous mental transformations provide clues to prior assumptions in visual imagery, just as visual illusions provide clues to perceptual assumptions. Visual imagery and perception share generic assumptions about invariants in images of rigid objects.

Norman's aim to reconcile two longstanding and seemingly opposed philosophies of perception, the constructivist and the ecological, by casting them as approaches to complementary subsystems within the visual brain is laudable. Unfortunately, Norman overreaches in attempting to equate direct perception with dorsal/unconscious visual processing and indirect perception with ventral/conscious visual processing. Even a cursory review suggests that the functional and neural segregation of direct and indirect perception is not as clear as the target article would suggest.

Pessoa et al. fail to make a clear distinction between visual perception and subjective visual awareness. Their most controversial claims, however, concern subjective visual awareness rather than visual perception: visual awareness is externalized to the “personal level,” thus denying the view that consciousness is a natural biological phenomenon somehow constructed inside the brain.