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.

Even today a good many distinguished minds seem unable to accept or even to understand that from a source of noise natural selection alone and unaided could have drawn all the music of the biosphere. In effect natural selection operates upon the products of chance and can feed nowhere else; but it operates in a domain of very demanding conditions, and from this domain chance is barred. It is not to chance but to these conditions that eveloution owes its generally progressive cource, its successive conquests, and the impresssion it gives of a smooth and steady unfolding.

Man finally knows that he is alone in the indifferent immensity of the Universe, from which he emerged by accident.

Je cherche à comprendre.

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.

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.

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.