Nominalism is the opposite position which says: only. Peter and Paul, only this tree, at Riverside Drive, at the corner of 116th (the big one there!): that alone exists, and not “treehood,” not the power of treehood, which makes it become one and which makes all the small ones develop – if the boys don’t destroy them! Here you have an example of the difference in feeling. If you look at a tree, you can feel nominalistically and say, “This is a real thing; if I run against it, I will hurt my head.” But you also can look at it and can be astonished, that of all the tree-seeds thrown into the soil, always this structure, shooting up and spreading its branches, etc., develops. And if you do this, then you can see in this big tree “treehood,” and not just a big tree. And in Peter and Paul, you can see not only these particular individuals, but also the nature of man, manhood, as a power which makes it possible that all men have this character.
The importance of this discussion, which went on in logical terms and is still going on all the time – there’s almost no day in which I do not have a fight against nominalism on the basis of my comparatively medieval realistic kind of thinking, which thinks that being is power-of-being. That is a sin against the “holy spirit” of nominalism, and therefore very much against the “unholy” spirit of logical positivism and many other such spirits. But I fight this fight because I believe that although extreme realism is wrong – namely that realism against which Aristotle was fighting in Plato, that the universals are special things somewhere in heaven – of course this has to be denied – – there are structures which actualize themselves again and again against all attempts of boys and stones and climate to make something else of them. They are always carried through. This is what I mean with “realism'”and so I can say, of being always resists non-being. And for this reason I believe that we cannot be nominalists alone, although the nominalist attitude, the attitude of humility towards reality, of not desiring to deduct reality, is something which we must maintain.
The immediate importance of nominalism was that it disrupted the universals, which were not only understood in terms of abstract concepts but which were also understood in terms of embracing groups – for instance, family, state, a group of friends, of craftsmen – where it is always the group which precedes the individual.
Now this was also the danger of medieval realism, that the individual was prevented from developing himself in his potentialities. Therefore nominalism was an important reaction, so important that I would say that without the nominalistic reaction the estimation of the personality in the modern world, (this real basis of democracy), couldn’t have developed. And while I usually make scolding remarks against our being nominalists, I now praise it, saying that without the emphasis on the fully developed individual and his potentialities we would have become Asiatics, as we are now in danger of becoming. And in this danger, medieval nominalism must be understood as positively as medieval realism. Medieval realism maintains the powers of being which transcend the individual; medieval nominalism preserves, or emphasizes, the valuation of the individual.