In most cases, to be reasonable means not to be obstinate, which in turn points to conformity with reality as it is. The principle of adjustment is t… - Max Horkheimer

Long after Plato’s time the concept of the Ideas still represented the sphere of aloofness, independence, and in a certain sense even freedom, an objectivity that did not submit to ‘our’ interests.

If the subjectivist view hold true, thinking cannot be of any help in determining the desirability of any goal in itself. The acceptability of ideals, the criteria for our actions and beliefs, the leading principles of ethics and politics, all our ultimate decisions are made to depend upon factors other than reason. They are supposed to be matters of choice and predilection, and it has become meaningless to speak of truth in making practical, moral or esthetic decisions.

In the world of action, we know that it is disastrous to treat animals or human beings as though they were stocks and stones. Why should we suppose this treatment to be any less mistaken in the world of ideas?