II.7. The object of sight is the visible, and what is visible is colour ...Whatever is visible is colour and colour is what lies upon what is in its own nature visible; 'in its own nature' here means not that visibility is involved in the definition of what thus underlies colour, but that that substratum contains in itself the cause of visibility. Every colour has in it the power to set in movement what is actually transparent; that power constitutes its very nature. That is why it is not visible except with the help of light; it is only in light that the colour of a thing is seen.

Aristotle, De Anima

This is the Phil 429 web page. Below is a course description and contact information for me. I'm not sure when or if I will be teaching this course again.

PHIL 429: SPECIAL STUDIES IN THE HISTORY OF PHILOSOPHY
Lect-D 10:00 MWF/Hilbert
Topic: Theory of Vision from Aristotle to Helmholtz
Vision is our main perceptual source of information regarding objects at a distance. The course will look at philosophical and psychological theories of how the visual system performs this important job from a historical perspective. Four main periods/authors will be looked at in detail: ancient theories of vision, particularly Aristotle; medieval theories of vision, particularly in the Islamic world; Berkeley's theory of vision; Helmholtz's theory of vision. Course requirements: term paper (15-20 pages), take-home quizzes, class participation.
Required text: David C. Lindberg, Theories of vision from Al-Kindi to Kepler.