Sorry I jumped without filling in the bits in-between. I didn't want to say that the separation of mind and body was an Enlightenment idea. That was another thought entirely, intended facetiously, which I tacked on to that paragraph.
I agree that there was a separation of mind and body in Plato's thought. This was essential to his theory in which the moral man is one who perceives the order of the universe despite the distraction of the inner longings of his body (likely an attack on Epicurean views). It's his theory of Ideas which causes the trouble I mentioned above. For OO, there has to be a separation between the natural world (data) and the world as we see and interact with it (code). The Enlightenment bit comes from Descartes internalist epistemology which describes why this is so.