It is our task to inquire into the causes that have brought about the observed differentiation, and to investigate the sequence of events that have led to the establishment of the multifarious forms of human life

We all know scientists who in private life do not come up to the standard of truthfulness, but who, nevertheless, would not consciously falsify the results of their researches

My parents had broken through the shackles of dogma

No one has ever proved that a human being, through his descent from a certain group of people, must of necessity have certain mental characteristics.

Remember that in every single case in history the process of adaptation has been one of exceeding slowness. Do not look for the impossible, but do not let your path deviate from the quiet and steadfast insistence on full opportunities for your powers.

There is no fundamental difference in the ways of thinking of primitive and civilized man. A close connection between race and personality has never been established.

The existence of any pure race with special endowments is a myth, as is the belief that there are races all of whose members are foredoomed to eternal inferiority.