In science, self-satisfaction is death. Personal self-satisfaction is the death of the scientist. Collective self-satisfaction is the death of the research. It is restlessness, anxiety, dissatisfaction, agony of mind that nourish science.

A curious aspect of the theory of evolution is that everybody thinks he understands it.

Among all the occurrences possible in the universe the a priori probability of any particular one of them verges upon zero. Yet the universe exists; particular events must take place in it, the probability of which (before the event) was infinitesimal. At the present time we have no legitimate grounds for either asserting or denying that life got off to but a single start on earth, and that, as a consequence, before it appeared its chances of occurring were next to nil. ... Destiny is written concurrently with the event, not prior to it.

Chance alone is at the source of every innovaton, of all creation in the biosphere. Pure chance, only chance, absolute but blind liberty is at the root of the prodigious edifice that is evolution... It today is the sole conceivable hypothesis, the only one that squares with observed and tested fact. Stating life began by the chance collision of particles of nucleic acid in the "prebiotic soup."

The fundamental biological variant is DNA. That is why Mendel's definition of the gene as the unvarying bearer of hereditary traits, its chemical identification by Avery (confirmed by Hershey), and the elucidation by Watson and Crick of the structural basis of its replicative invariance, are without any doubt the most important discoveries ever made in biology. To this must be added the theory of natural selection, whose certainty and full significance were established only by those later theories.

Man's destiny is nowhere spelled out, nor is his duty.

...the scientific attitude implies what I call the postulate of objectivity-that is to say, the fundamental postulate that there is no plan, that there is no intention in the universe. Now, this is basically incompatible with virtually all the religious or metaphysical systems whatever, all of which try to show that there is some sort of harmony between man and the universe and that man is a product-predictable if not indispensable-of the evolution of the universe.