The Society for Ancient Greek Philosophy Newsletter

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In this paper, I would like to sketch my account of the relation between cognitive activity and material alteration within Aristotle's psychological theory. I will begin by suggesting a new framework through which to view the important issues (§2). I will then show that on Aristotle's account material alteration is required both for any episode of perception in animals taken generally (§3) and for any episode of thought in human beings (§4). Finally, I will examine Aristotle's rationale for supposing that material alteration is required for human thought (§5).


John Sisko presented “Material Alternation and Cognitive Activity in Aristotle’s De Anima” at the meeting of the Society with the Eastern Division of the American Philosophical Association in New York in 1995. A revised version was published in Phronesis 41.2:138-157 (1996).

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