lives its own life, looks for well-being for itself and attains it by grouping and associating itself with others. In short, each individual is a cosmos of organs, each organ is a cosmos of cells, each cell is a cosmos of infinitely small ones; and in this complex world, the well-being of the whole depends entirely on the sum of well-being enjoyed by each of the least microscopic particles of organised matter. A whole revolution is thus produced in the philosophy of life.
But it is especially in psychology that this revolution leads to consequences of great importance.
Quite recently the psychologist spoke of man as an entire being, one and indivisible. Remaining faithful to religious tradition, he used to class men as good and bad, intelligent and stupid, egotists and altruists. Even with materialists of the eighteenth century, the idea of a soul, of an indivisible entity, was still upheld.
But what would we think to-day of a psychologist who would still speak like this! The modern psychologist sees in man a multitude of separate faculties, autonomous tendencies, equal among themselves, performing their functions independently, balancing, opposing one another continually. Taken as a whole, man is nothing but a resultant, always changeable, of all his divers faculties, of all his autonomous tendencies, of brain cells and nerve centres. All are related so closely to one another that they each react on all the others, but they lead their own life without being subordinated to a central organ—the soul.
Without entering into further details you thus see that a profound modification is being produced at this moment in the whole of natural sciences. Not that this analysis is extended to details formerly neglected. No! the facts are not new, but the way of looking at them is in course of evolution; and if we had to characterise this tendency in a few words, we might say that if formerly science strove to study the results and the great sums (integrals, as mathematicians say), to-day it strives to study the infinitely small ones—the individuals of which those sums are composed and in which it now recognizes independence and individuality at the same time as this intimate aggregation.
As to the harmony that the human mind discovers in Nature, and which harmony is, on the whole, but the verification of a certain stability of phenomena, the modern man of science no doubt recognizes it more than ever. But he no longer tries to explain it by the action of laws conceived according to a certain plan preestablished by an intelligent Will.
What used to be called "natural law" is nothing but a certain relation among phenomena which we dimly see, and each "law" takes a
