Abstract

In this work I reconstruct the physical and mental descriptions of perception in Aristotle. I propose to consider the thesis that αἴσθησις is a μεσότης (DA II 11) as a description of the physiological aspect of perception, meaning that perceiving is a physical act by which the sensory apparatus homeostatically counterbalances, and thence measures, the incoming affection produced by external perceptible objects. The proposal is based on a revision of the semantics of the word mesotês in Plato, Aristotle and later Greek mathematicians (mostly Nicomachus of Gerasa). I show how this interpretation fits the text, and how it solves problems that afflict the rival interpretations. I further develop a ‘non-dephysiologizing’ spiritualist reading of the additional description of perception as reception of forms without the matter (DA II 12). I show that Aristotle uses the expression ‘forms without matter’ to describe actually abstracted items in one’s mind rather than the way in which the form are received. In opposition to forms-in-matter, such items are causally powerless and metaphysically sterile: an F-without-matter somewhat determines the subject it is in (one’s mind content F) without qualifying or identifying it as an F-subject. Thus, we have a second ‘mental’ description of perception. Further parts of the thesis are devoted to settle interpretive questions raised by controversial statements about perception found in De Anima II 5 and III 2, and to discuss the question of how the mental and physiological descriptions of perception Aristotle offers are related. My conclusion is that Aristotle’s views combines a form of quasi-dualist vitalism about powers (the faculty of perception, and more generally the soul, are not just irreducible to matter, but also primitive and non-supervenient) which is nonetheless compatible with hylomorphism, and a form of epiphenomenalism (and thence the ‘bottom-up’ determination typical of modern supervenience) with regard to perceptual events (i.e., the activity of perceiving).