Observers, objects, and the embedded eye; or, seeing and knowing in Ptolemy and Galen.

This essay explores the ways in which theories and entities are culturally and intellectually embedded in historical and disciplinary contexts by looking at the development of a set of related theories of perception that emerged in response to contemporary Sceptical criticisms of the very possibility of doing empirical science. At the same time, it attempts to bring into focus a puzzle about precisely how (and how deeply) seeing itself is conditioned.