Authoritarian thinkers have conveniently assumed the existence of a human nature, which they believe was fixed and unchangeable. This assumption served to prove that their ethical systems and social institutions were necessary and unchangeable, being built upon the alleged nature of man. However, what they considered to be man’s nature was a reflection of their norms – and interests- and not the result of objective inquiry. It was therefore understandable that progressives should welcome the findings of anthropology and psychology which, in contrast, seemed to establish the infinite malleability of human nature. For malleability meant that norms and institutions – the assumed cause of man’s nature rather than the effect – could be malleable too. But in opposing the erroneous assumption that certain historical cultural patterns are the expression of a fixed and eternal human nature, the adherents of the theory of the infinite malleability of human nature arrived at an equally untenable position. First of all, the concept… easily leads to conclusions which are as unsatisfactory as the concept of a fixed and unchangeable human nature. …[N]orms and institutions unfavorable to human welfare would have a chance to mold man forever into their patterns without the possibility that intrinsic forces in man’s nature would be mobilized and tend to change these patterns. Man would be only the puppet of social arrangements and not – as he has proved to be in history – an agent whose intrinsic properties react strenuously against the powerful pressure of unfavorable social and cultural patterns. In fact, if man were nothing but the reflex of culture patterns no social order could be criticized or judged from the standpoint of man’s welfare since there would be no concept of “man.”
…Man can adapt himself to slavery, but he reacts to it by lowering his intellectual and moral qualities; he can adapt himself to a culture permeated by mutual distrust and hostility, but he reacts to this adaptation by becoming weak and sterile. Man can adapt himself to cultural conditions which demand the repression of sexual strivings, but in achieving this adaptation he develops, as Freud has shown, neurotic symptoms. He can adapt himself to almost any cultural pattern, but in so far as these are contradictory to his nature he develops mental and emotional disturbances which force him eventually to change these conditions since he cannot change his nature.
Man is not a blank sheet of paper on which culture can write its text; he is an entity charged with energy and structured in specific ways, which, while adapting itself, reacts in specific and ascertainable ways to external conditions. If man had adapted himself to external conditions autoplastically, by changing his own nature, like an animal, and were fit to live under only one set of conditions to which he developed a special adaptation, he would have reached the blind alley of specialization which is the fate of every animal species, thus precluding history. If, on the other hand, man could adapt himself to all conditions without fighting those which are against his nature, he would have had no history either. Human evolution is rooted in man’s adaptability and in certain indestructible qualities of his nature which compel him never to cease his search for conditions better adjusted to his intrinsic needs.