Aristotle’s Theory of Colors between Physics and Physiology

Abstract

First of all, this article illustrates the conceptions of vision and colors elaborated by Greek philosophers up to Aristotle. Then it shows that Aristotle in his theory of color profits from the reflection on this theme by previous thinkers, but at the same time formulates a conception of remarkable originality, which organically frames itself in his doctrine of sensation, and in particular of vision. For Aristotle, in fact, in order that the vision of an object can happen, a transparent (or diaphanous) body is needed, such as air or water, which acts as a medium between the object itself and the observer. If there is a light source, the medium becomes actually transparent, and as a consequence, the object becomes actually visible and transmits its shape and color to the observer’s eye. In the absence of light, on the other hand, the medium remains potentially transparent: in this case, although the object has its shape and color - which are its properties -, it is not actually visible, but only potentially, and so are its shape and its color.