It was the trick of the ages for the philosopher, high up on a pedestal, to discuss the immutable laws of irrational nature in the cosmos, without including the rational philosopher himself as a part of nature. It was “Hic homo, hic natura.” The truth of evolution has swept away for ever this kind of sophistry. Evolution teaches unity in nature. The mineral, vegetable and animal kingdoms are composed of the same elements. The transition from one kingdom into another is almost imperceptible. There is no line to be drawn between living and non-living matter. Botanists and zoologists are often at a loss to determine to which kingdom certain specimens belong.[DP] There is unity in nature, and man is no less an integral part of nature than the air or the stars. Now, man is a rational being. Hence an integral part of nature is rational, and there is rationality in nature. If a thousand millions of human brains, or a thousand million kilograms of brain-matter on our planet possess intelligence, reason, wisdom, judgment, memory, foresight, mind and ideas, then there is rationality in nature. Even if this rationality is now only perceivable in the human brain, it must, eons ago, have been present in potentiality in the primordial cell, which developed into the human brain, the flower of organic life. Nay, rationality must have transcended the primordial cell. “The soul, or the power of judgment, being the factor that makes experience possible,” says Bergson, “cannot be a complex of experience only, it transcends experience.” The soul, mind and body become a unity in man, a trinitarian unity, a “Dreieinigkeit.” There is interdependence between the physical and the mental. The higher psychic centres are dominated and domineered by the lower, or vegetative centres. But two things, mutually dependent, are not for that matter equivalent. The subtle and delicate influences by which soul and body affect each other do not make them identical. The mind which includes intellect and emotion is something entirely different from the brain-cell. The action between mind and brain-cell is absolutely unknown to us.