Considered in its entirety, psychoanalysis won't do. It is an end product, moreover, like a dinosaur or a zeppelin; no better theory can ever be erected on its ruins, which will remain for ever one of the saddest and strangest of all landmarks in the history of twentieth century thought.

If a scientist were to cut his ear off, no one would take it as evidence of a heightened sensibility.

A scientist is no more a collector and classifier of facts than a historian is a man who complies and classifies a chronology of the dates of great battles and major discoveries.

Is the Scientific Paper a Fraud?

Scientific reasoning is a dialogue between the possible and the actual, between proposal and disposal between what might be true, and what is in fact the case.

The alternative to thinking in evolutionary terms is not to think at all.

It is ... a sign of the times-though our brothers of physics and chemistry may smile to hear me say so-that biology is now a science in which theories can be devised: theories which lead to predictions and predictions which sometimes turn out to be correct. These facts confirm me in a belief I hold most passionately-that biology is the heir of all the sciences.