Abstract

I consider the geometrical structure of the apparent visual field. Although the optics of vision is well understood, the nature of visual awareness remains largely in the dark. A famous attempt at a formal description of the apparent visual field was by Helmholtz, in the late nineteenth century. It purportedly explains the phenomenon of the subjective curvatures often reported when viewing objectively straight lines of great extent. I consider the general problem, and suggest an alternative formal account. On phenomenological grounds the very existence of a coherent geometry may be doubted. Yet, although seemingly an academic question, the issue has very real consequences. The two models I consider here may approximately apply to certain visual modes. The nature of such visual modes is discussed.