ABSTRACTThomas Aquinas argues that the agent intellect's function is to abstract an intelligible species from a phantasm. However, insofar as he claims that the intelligible species is not present in the phantasm, it is unclear how the agent intellect accomplishes this task. In this paper I explore two models of abstraction – the extraction model and the production model – suggesting that each fails to capture Aquinas’ understanding of abstraction. I then offer my own interpretation of the function of the (...) agent intellect – the illumination model – by employing Aquinas’ comparison of the agent intellect to light. I argue that the agent intellect neither extracts nor produces an intelligible species, but rather makes the nature that is already present in the object intelligible by actualizing its passive power of intelligibility. This involves the co-actualization of partner powers in the intellect and in the intelligible object, and ultimately makes it possible to cognize a particular, material object in a universal way. (shrink)