A Blackfoot Indian, when arguing with a Christian missionary, said: “There were two religions given by the Great Spirit, one in a book for the guidance of the white men, who, by following its teaching, will reach the white man’s heaven; the other is in the heads of the Indians, in the sky, rocks, rivers and mountains. And the red men who listen to God in nature, will hear his voice, and find at last the heaven beyond.” These Indians consider that that external nature which to us is at the same time the veil and the revelation of the Divine, is sufficient to teach them so much concerning the Supreme Being that missionaries are superfluous. Amongst those whose thoughts are occupied by the origin of religious perception in man, there exist several theories; the first, that the idea of infinity is a necessity to the mind of man, and that by enlarging the boundaries of space and of time, it arrives at that which is without space and without time. Thus may a true philosopher reason; but primitive man was no philosopher, and the infinite of philosophy had no existence for him. Another theory is that man is naturally endowed with religious instincts, which render him--alone of all living creatures--capable of perceiving the infinite in the invisible; but the nature of this innate instinct not being clearly defined, it is in vain that we try to explain one mystery by another. Others again affirm that religious impressions were the result of a supernatural revelation, but they seem vague with regard to the time in the life of humanity, to which people, and in what manner this came to pass. At the same time they draw attention to the fact that men have always arrived at conclusions rapidly, and, as they consider, without due reflection; one of these conclusions is that _God is_. Let us, for the sake of argument, replace the word _man_ by the word _intuitive sense_ or apprehension, and we shall understand why this intuitive sense renders it a superfluous task to make great researches as to the reasons of man’s decision that _God is_. This intuitive sense is wise, and utters at times great truths; but the philosophers who consider it their metier to seek for the reason of things are not content with what satisfies intuitive sense, and they act on their right. In our days the religious problem is viewed from two sides. What is understood by these words--the conception of God? This is the question of questions; and the names of the writers on the subject, both philosophical and theological, are too numerous to give. It is a psychological and thought impelling study. How did the idea of God first arise in the minds of primitive man? This is another question which few try and answer. It is a historical study.