Consciousness appears at a particular moment in the evolution of the individual as in that of the race. This emergence of the spiritual beyond the material, beyond the mass of cells and blood which make up the organism, is an immediate datum of observation. It constitutes an essential character of the substance of which we are made. Human life begins in the night of the spirit. The ovule, even when it potentially contains the genius of Newton, Goethe or Napoleon, differs little from those unicellular creatures which during the Archeozoic period of the Precambrian age, represented the humble beginning of living things on the earth's surface. Once fertilized, the ovule divides and engenders the embryo; the embryo becomes the fetus; the child is born. But the night continues until those wonderful moments in the first year when the mother sees the dawn of intelligence arise in her baby's eyes. Like morning light in the tropics, intelligence grows fast In a few dozen months, a human child journeys the whole road which it took living forms perhaps more than a thousand million years to traverse in their ascent toward mind. From the mental, as well as from the bodily point of view, the evolution of the individual presents some analogy, as Haechel supposed, with the evolution of the species. The phylogenic evolution of mind appears to prefigure the ontogenic.
Mental development is at once automatic and voluntary. In infancy it is entirely automatic, as in the development of organs, muscles and bones. It is only later that it asks help from the intelligence and the will. At first the mind grows, along with the nervous system and the other tissues, under the internal impulse of the hereditary forces which have their seat in the genes of all the cells of the organism. It is the influence of the genes which gives it, like the features of our face, a certain likeness to our parents or to certain of our ancestors. Nevertheless, the actualization of inherited potentialities is not inevitable. It depends on the physical and chemical conditions of the environment in which the individual develops. This is why many individuals remain inferior all their life to what they might have been. The soul is not independent of the body; the quality of the mind depends on that of the organs, particularly that of the brain and the endocrine glands. No microcephalous genius has ever appeared. If Virgil had been the victom of thyroidal myxedema or of pancreatic diabetes, he would not have written the Aeneid. It is true, however, that the great soul can inhabit a sickly body. Sometimes disease is not incompatible with a highly elevated mind; St. Therese of Lisieux was tubercular. Syphilis, on the contrary, often injures the brain but sometimes gives a splendid richness to thought. Alphonse Daudet suffered from locomotor ataxia; Guy de Maupassant died of general paralysis. There are organic defects which attack the soul and others which leave it undamaged. But the state of consciousness is never wholly independent of the state of the tissues, body fluids and blood.
The spontaneous growth of the mind always remains incomplete. Man can only give full play to his mind by the effort of his own will. One cannot become an athlete without training. In the same way one has to work hard to increase one's powers of awareness. If a pupil has no will to learn, the most brilliant schoolmaster can teach him nothing. Reading moral treatises will not make us virtuous. Only we ourselves can forge our own souls.
The formation of personality is equivalent, to use Berg-son's expression, to the creation of the self by the self. This' creation of the self by the self consists in drawing from our body and our consciousness more than they contain; in modeling our interior life according to an ideal. We have to construct in ourselves, with the help of materials which may often be mediocre, a new and powerful spirit. This miracle occurs every day in the history of mankind. Great men often arise from the humblest origins. But all, ignorant and learned, rich and poor, young and old, are equally capable, if they are really determined, of releasing the hidden spiritual energy in their own depths. Though consciousness develops side by side with the body it does not stop developing when the body has finished growing.