 According to the standard medieval realist theories of knowledge, as exemplified by Thomas Aquinas and Giles of Rome, the primary object of the human intellect is the essence of material things. Such essences become intelligible to us only when our intellect has abstracted them from the individualising properties connected with the matter, so that we can have direct knowledge of universals only. Yet, an intellective knowledge of individuals is possible, if the intellect, after abstracting the intelligible species through which it grasps essences, turns its attention to the phantasm from which it has drawn the intelligible species itself. This action, the conversion to phantasm, produces a reflexive (that is, indirect) and incomplete knowledge of the individual thing represented by the phantasm itself. On the other hand, according to the standard medieval nominalist theories of knowledge, as exemplified by Ockham, individuals alone are the object of our intellect, and the main form of human cognition is not the abstractive one, but intuitive cognition, which properly concerns the existence and non-existence of individual things, as it is that immediate apprehension of a thing (that is, an individual substance or quality) as existent which enables us to form a contingent proposition concerning the existence of that same thing. By contrast, abstractive knowledge is an apprehension of terms by which it is impossible for us to have evidence of whether or not a certain thing exists. Thus, intuitive and abstractive cognition attain the same singular objects, but in different ways, since abstractive cognition is indifferent to existence and produces a universal sign of a multiplicity of singulars.