The reason for it is the following: For medieval man, the universals, the essences, the nature of things, the nature of truth, the nature of man, are powers which determine what every individual tree or every individual man always will become when he or it develops. This is, if you want, mystical realism or, if you want, idealism. Universalia realia – this is medieval realism. They are not, of course, things in time and space; that is a misunderstanding, and then it is a little too easy to reject them and say, “I have never seen “manhood,” I have only seen “Paul” and “Peter”.

Of course this is a wisdom the medieval people, also, knew. But they said all Pauls and Peters always have a nose and eyes and feet and language – this is a phenomenon which must be understood, and it can be understood only if it is understood in terms of the universal, the power of being which we call manhood, and which makes it possible for every man again to become a man, with all these potentialities – which may not develop, which may be destroyed; but he has these potentialities. That is what realism means.