Aristotle is clearly aware that the theory of separable intellect is not without its own difficulties. One difficulty is that of how intellect is to come to possess its objects. These objects first exist (potentially) in material things, but material things (it would seem) share no underlying generic sameness with separable (immaterial) intellect. So, upon consideration of his own account of agency and patiency, which requires that agent and patient hold something in common (see Generation and Corruption 1.7), it becomes unclear to Aristotle how it is that separable intellect, having nothing in common with anything else, is to ever come to think, (see DA III.4, 429b21- 26). Aristotle, then, is not entirely at ease with the theory of separable intellect. Further, it is plausible that part of his later discussion of intellect (in DA III.5-8) is aimed at resolving problems within his initial account and it is plausible that he aims at resolving these problems by establishing the dependence of thought upon the body. In DA III.5, Aristotle introduces the active intellect and the passive intellect. These, on one plausible interpretation, are the efficient and material cause of thought respectively. Aristotle does not claim of passive intellect, as he does of active intellect, that it is separable, rather he claims that it is perishable, (see 430al7 & 430a4-25). This suggests that passive intellect is more closely linked with the body than is active intellect and this, I take it, is a sign that Aristotle strives towards a more hylomorphic account of intellect in DA III.5. Further, in DA III.7-8, Aristotle argues for the thesis that episodes of thought are dependent upon the use (or activation) of images (φαντάσματα). Images are, for Aristotle, material items stored in the common sensorium. (see De Memoria 450a26-bl). So, this thesis requires that material change (bodily change) is a necessary condition for episodes of thought. This, I take it, is a sign that Aristotle strives towards a more hylomorphic account of intellect in DA III.7-8. So, both in DA III.5 and DA III.7-8 we find elements within Aristotle ’s discussion of intellect that suggest he ultimately strives to ease the tension between his initial account of'intellect in DA III.4 and his standard model for explaining psychological capacities (hylomorphism).
Sisko, John E., "On Separating the Intellect from the Body: Aristotle's De Anima III.4, 429a10-b5" (1999). The Society for Ancient Greek Philosophy Newsletter. 202.