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 knows at last that he is alone in the universe's unfeeling immensity, out of which he emerged only by chance.

One may well find oneself beginning to doubt whether all this could conceivably be the product of an enormous lottery presided over by natural selection, blindly picking the rare winners from among numbers drawn at utter random...nevertheless although the miracle of life stands "explained" it does not strike us as any less miraculous. As Francois Mauriac wrote, What this professor says is far more incredible than what we poor Christians believe.

What is true for E. coli is also true for the elephant.

Armed with all the powers, enjoying all the wealth they owe to science, our societies are still trying to practice and to teach systems of values already destroyed at the roots by that very science. Man knows at last that he is alone in the indifferent immensity of the universe, whence which he has emerged by chance. His duty, like his fate, is written nowhere.

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

The scientific attitude implies the postulate of objectivity-that is to say, the fundamental postulate that there is no plan; that there is no intention in the universe.