The fact abides that the great mass of supernatural beliefs which have persisted from the lower culture till now, and which are still held by an overwhelming majority of civilized mankind, are referable to causes concomitant with man's mental development: causes operative throughout his history. The low intellectual environment of his barbaric past was constant for thousands of years, and his adaptation thereto was complete. The intrusion of the scientific method in its application to man disturbed that equilibrium. But this, as yet, only superficially. Like the foraminifera that persist in the ocean depths, the great majority of mankind have remained, but slightly, if at all, modified; thus illustrating the truth of the doctrine of evolution in their psychical history. (For that doctrine does not imply all-round continuous advance. "Let us never forget," Mr. Spencer says in Social Statics, "that the law is--adaptation to circumstances, be they what they may.") Therefore the superstitions that still dominate the life of man, even in so-called civilized centres, are no stumbling-blocks to us. They are supports along the path of inquiry, because we account for their persistence. Thought and feeling have a common base, because man is a unit, not a duality. But the exercise of the one has been active from the beginnings of his history--indeed we know not at what point backward we can classify it as human or quasi-human--while the other, speaking comparatively, has but recently been called into play. So far as its influence on the modern World goes, may we not say that it began at least in the domain of scientific naturalism with the Ionian philosophers? Emotionally, we are hundreds of thousands of years old; rationally, we are embryos.