The principles involved in the solution of this problem evidently led to a very important inference, at this early period betraying what was before long to become a serious point of dispute. It is natural for man to see in things around him visible tokens of divinity, continual providential dispensations. But in this, its very first act, Greek philosophy had evidently excluded God from his own world. This settling of the heavy, this ascending of the light, was altogether a purely physical affair; the limitless sea, the blue air, and the unnumbered shining stars, were set in their appropriate places, not at the pleasure or by the hand of God, but by innate properties of their own. Popular superstition was in some degree appeased by the localization of deities in the likeness of men in a starry Olympus above the sky, a region furnishing unsubstantial glories and a tranquil abode. And yet it is not possible to exclude altogether the spiritual from this world. The soul, ever active and ever thinking, asserts its kindred with the divine. What is that soul? Such was the second question propounded by Greek philosophy. [Sidenote: Second problem. What is the soul?] [Sidenote: Its material solution thereof.] A like course of superficial observation was resorted to in the solution of this inquiry. To breathe is to live; then the breath is the life. If we cease to breathe we die. Man only becomes a living soul when the breath of life enters his nostrils; he is a senseless and impassive form when the last breath is expired. In this life-giving principle, the air, must therefore exist all those noble qualities possessed by the soul. It must be the source from which all intellect arises, the store to which all intellect again returns. The philosophical school whose fundamental principle was that the air is the primordial element thus brought back the Deity into the world, though under a material form. Yet still it was in antagonism to the national polytheism, unless from that one god, the air, the many gods of Olympus arose. [Sidenote: Third problem. What is God?] But who is that one God? This is the third question put forth by Greek philosophy. Its answer betrays that in this, its beginning, it is tending to Pantheism. In all these investigations the starting-point had been material conceptions, depending on the impressions or information of the senses. Whatever the conclusion arrived at, its correctness turned on the correctness of that information. When we put a little wine into a measure of water, the eye may no longer see it, but the wine is there. When a rain-drop falls on the leaves of a distant forest, we cannot hear it, but the murmur of many drops composing a shower is audible enough. But what is that murmur except the sum of the sounds of all the individual drops? [Sidenote: Fourth problem. Has man a criterion of truth?]