147. Conclusion. -- Extreme realism attends only to the real element in our concepts and endows this element with actual universality. As against this, the earlier forms of anti-realism urge the negative thesis of the non-existence of universal essences. Both theories alike offer an imperfect solution of the problem; but, whereas the first is vitiated by a fundamental error, the second embodies a true doctrine which a series of more searching investigations and more accurate formulas were destined gradually to bring to light.

From the standpoint of the development of scholastic philosophy, the two parties, "realists" and "nominalists," differed in the lines of influence they exerted. The former, more concerned with the substantial reality of things, contributed powerfully to the study of metaphysics. The latter, bent on demolishing mere chimerical creations, were not at all clear nor sure of their ground when it came to determining the precise relations between reality and thought. In order to discover how a universal concept could represent an individual thing they had to investigate the genesis of knowledge and to bring to light the laws of abstraction and reflexion. Thus, it was the gradual study of psychological problems that was fostered in the schools of the anti-realists.