By constitution (or endowment) we mean more than just temperament in the classic sense. Rather, we refer to the basic structure of personality. Relationships in the family either help bring out this structure to its best fruition, or they tend to distort it. Just as a pear seed cannot produce an apple tree, but only better or worse pear trees, depending on the conditions of soil and climate, so a child can only develop his given potential structure in the most harmonious vital form or in a negative form. For instance, a highly sensitive and unaggressive child may become, under favorable influences, an introspective, artistic and spiritual-minded person. Under the influence of cold and authoritarian parents, the same child is likely to become intimidated, frightened, and resentful, with the result that he wastes most of his energy by not being able to be what he potentially is. ― (1970b [with Michael Maccoby]: Social Character in a Mexican Village. A Sociopsychoanalytic Study, Englewood Cliffs (Prentice Hall) 1970, p. 20.)
Constitutional factors cover not only factors, which are usually defined as temperament (…), but also factors such as vitality, love of life, courage, and many other things which I don’t even want to mention. In other words, I think a person, in the lottery of the chromosomes, is already conceived as a very definite being. The problem of a person’s life, really, is what life does to that particular person who is already born in a certain way. Actually, I think it’s a very good exercise for an analyst to consider what would this person be if life conditions had been favorable to that kind of being he was conceived as, and what are the particular distortions and damages which life and circumstances have done to that particular person. ― (1991c [1964] Factors Leading to Patient’s Change in Analytic Treatment, in: E. Fromm, The Art of Listening, New York (The Continuum Publishing Corporation) 1994, p. 33.)