Aristotle

The founder of the ‘The Lyceum’ and tutor of Alexander the Great.   Aristotle differs with his teacher Plato concerning the reality and comprehensibility of the ‘Ideal’.   Radical idealism, the notion that the universal concepts of things are of greater force than the perception of the particular things themselves, is countered with a tempered view that the particulars are necessary to our knowledge of the ‘Ideal’.  It may even be said that the real ideas arise from the entelechy of things themselves. (see the four causes.)