St. Thomas Aquinas calls Aristotle “The Philosopher” as a mark of respect that he is the best. But Plato is also considered a great philosopher and a genius. The two of them had different views on what constitutes basic reality (metaphysics or the ground of being). Plato who actually taught Aristotle, had a metaphysics that said the ultimate reality is in the world of Ideas where the essences of things resided. For example, there are many tables on earth but in the world of Ideas, there is the ultimate table or the perfect idea of a table. It’s not a physical reality but a spiritual one, and the point is that the really real world-- is the world of ideas. Aristotle taught that the essence or true being of something (like a table) exists in the thing itself, in the form of the thing. So in every table that exists on earth, it has a form of “table-ness” that holds the true essence of being a table. This is a simplified answer but that is the basic concept. Plato also thought that learning was a type of remembering what we once knew but had forgotten. I think he believed in some version of re-incarnation. Overall, Aristotle is considered more a scientist type of philosopher because he taught that we learned through our senses interacting with the physical world. Aristotle taught that the permanent things and the changeable things exists with and in each other: one, substance (permanent) and the other accidents (changeable). An example of this is the teaching of the church on the Eucharist, where we believe the bread and wine change into the Body and Blood of Jesus. It still looks like bread and wine but the substance or form or essence of it changes into the Lord, while the accidents or matter continue looking like bread and wine. The true substance or essence changes only. I hope this helps a little bit. Patrick