In every philosophy of the universe, the question concerning the primary cause of the phenomena of nature always arises. Ancient and modern philosophers, alike, have discussed the probability of the existence of this primary cause and its properties. Plato, putting the words into the mouth of Socrates, declares, "I do believe in the Gods."[A] Aristotle, the greatest of early thinkers, assumed that a God exists, from whom all other forces are derived. For example, "From a first principle, then, of this kind--I mean, one that is involved in the assumption of a First Mover--hath depended the Heaven and Nature."[B] Spencer, speaking in these latter days, likewise implies the existence of the equivalent of the God of men, thus, "If religion and science are to be reconciled, the basis of reconciliation must be this deepest, widest and most certain of all facts--that the Power which the universe manifests to us is utterly inscrutable."[C] [Footnote A: Plato, The Apology, chap. XXIV.] [Footnote B: Aristotle, Metaphysics, chap. VII, sec. 4.] [Footnote C: First Principles, p. 48.] To the great majority of men, in all ages, the idea of a God or Power, has appeared to be a necessity. Naturally, there has been a great variety of opinions concerning the nature of God, or the great Power behind things. Some, including the early Greek thinkers, looked upon God as a personal being of transcendental attributes; others gave Him a more shadowy form, and made of Him nothing more than an all pervading spiritual essence. Still others, considering the relations of all natural operations to the infinite power of God, identified Him with Nature, and then, with astonishing shortsight denied His personal existence. Thus, by degrees, arose the various theists, who accepted a personal God with varying attributes; the pantheists, who identified God with nature, and the atheists, who denied absolutely God, or any equivalent. Among those who have adopted the idea of God, the chief dispute has been largely as to His personality; to the atheists the essential consideration has been that the laws of nature are self-operative and need no directing force such as is implied in the conception of a God. [Sidenote: Science points to a force of forces.]