Middle Platonism is not only the result of the exegesis of Plato’s dialogues; it is also the consequence of its engagement with other schools and philosophical movements. Most important, with regard to the problem of knowledge, is its appropriation of some of the cardinal tenets of Stoic epistemology and in particular of ennoiai (notions). Middle Platonism adopted the Stoic theory of ennoiai but argued that such a theory needed to be reinterpreted in an innatist sense in order to provide a real foundation for knowledge. It is only when ennoiai are supported by Ideas that they can be used as a reliable starting-point for knowledge (episteme). In this sense Middle Platonist epistemology can be seen as a revised, metaphysically- oriented, version of Stoic epistemology. A similar strategy was also adopted in the case of Aristotelian intuition. The problem is that at the same time Middle Platonists also admitted that we do not have proper knowledge of Ideas in our incarnate life and this risks paving the way for skepticism, which is what Plotinus would reproach his predecessors with.
Keywords: Middle Platonist epistemology, Plato’s theory of ideas, Stoic epistemology, the problem of the criterion, intuition, Aristotle’s theory of intellect