 The agent intellect endows the quiddity with intelligibility: through its act of abstraction it makes universal and immaterial the material and particular quiddity in the sensory representation (In De an.: q.12 and q.16). Simon, however, wavers between different descriptions of the act of abstraction. On one hand, he describes it as similar to the act of illumination, so that just as light enables the eye to see and the visible object to be seen, so the agent intellect enables the possible intellect to think and the quiddity in the sensory representation to be thought (In De an.: q.12). Consequently, he seems to consider intellection as similar to the act of vision. Nonetheless, the similarity is not complete, because the visible object is visible in itself, whereas the quiddity in the sensory representation must be made intelligible by the agent intellect. On the other hand, Simon describes the act of abstraction as the extraction of an intelligible species from the sensory representation, a species that is ‘re-positioned’ in the possible intellect, thus actualizing its act of apprehension (In De an.: q.16). Later commentators would reject one or the other model of abstraction depending on the extent of their realism about essences. Thus, the Averroist master John of Jandun rejects the illumination model because there is no way for something that exists in a bodily organ to be made universal, whether by illumination or otherwise, while remaining in that organ. Radulphus Brito, however, rejects the ‘re-positioning’ model because it fails to explain the transfer of a form from the material to the immaterial realm. Simon, it seems, is again unaware of the conflicts each model faces, as well as of the difficulties that would arise from holding both.