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

Je cherche à comprendre.

...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.

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."

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.

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.

Evolution in the biosphere is therefore a necessarily irreversible process defining a direction in time; a direction which is the same as that enjoined by the law of increasing entropy, that is to say, the second law of thermodynamics. This is far more than a mere comparison: the second law is founded upon considerations identical to those which establish the irreversibility of evolution. Indeed, it is legitimate to view the irreversibility of evolution as an expression of the second law in the biosphere.