 The work of the agent intellect had seemed essential because of a widely held view regarding the object of knowledge. This held that while the senses deal with particular individuals, the intellect can grasp only their universal properties. As Aquinas writes, citing Aristotle (APo. 87b37–39), “sense has to do with particulars, whereas intellect has to do with universals” (sensus particularium, intellectus … universalium) (Aquinas In DA 2.5 [sect. 284]). (The idea that the intellect has direct knowledge only of universals seems distinctively Aristotelian; it was not shared by other ancient philosophical schools [Normore 2007: 114].) Aquinas’s reason for holding this view is that the intellect, as an immaterial substance, cannot directly grasp material singulars. Intellectual knowledge therefore requires the work of the agent intellect, abstracting the immaterial intelligible forms from the perceptible forms grasped by the senses. We do, of course, know singular objects, for all the objects of sensation are, ultimately, singulars. But in Aquinas’s view, the intellect knows these objects only indirectly, by directing its attention back to the images yielded by the senses and linking these with the associated general concept (Aquinas ST 1a 86.1).