We may, it is true, ask ourselves whether the genealogical method permits results so far divergent as those presented to us by variety of species. But embryology answers by showing us the highest and most complex forms of life attained every day from very elementary forms; and palaeontology, as it develops, allows us to witness the same spectacle in the universal history of life, as if the succession of phases through which the embryo passes were only a recollection and an epitome of the complete past whence it has come. In addition, the phenomena of sudden changes, recently observed, help us to understand more easily the conception which obtrudes itself under so many heads, by diminishing the importance of the apparent lacunae in genealogical continuity. Thus the trend of all our experience is the same. Now there are some certainties which are only centres of concurrent probabilities; there are some truths determined only by succession of facts, but yet, by their intersection and convergence, sufficiently determined. "That is how we measure the distance from an inaccessible point, by regarding it time after time from the points to which we have access." ("Report of the French Philosophical Society", meeting, 2nd May 1901.) Is not that the case here? The affirmative seems all the more inevitable inasmuch as the language of transformism is the only language known to the biology of today. Evolution can, it is true, be transposed, but not suppressed, since in any actual state there would always remain this striking fact that the living forms met with as remains in geological layers are ranged by the natural affinity of their characteristics in an order of succession parallel to the succession of the ages. We are not really then inventing a hypothesis in beginning with the affirmation of evolution. But what we have to do is to appreciate its object. Evolution! We meet the word everywhere today. But how rare is the true idea! Let us ask the astronomers who originate cosmogonical hypotheses, and invent a primitive nebula, the natural philosophers who dream that by the deterioration of energy and the dissipation of movement the material world will obtain final rest in the inertia of a homogeneous equilibrium, let us ask the biologists and psychologists who are enemies of fixed species and inquisitive about ancestral history. What they are anxious to discern in evolution is the persistent influence of an initial cause once given, the attraction of a fixed end, a collection of laws before the eternity of which change becomes negligible like an appearance. Now he who thinks of the universe as a construction of unchangeable relations denies by his method the evolution of which he speaks, since he transforms it into a calculable effect necessarily produced by a regulated play of generating conditions, since he implicitly admits the illusive character of a becoming which adds nothing to what is given.