Plato continues: “Since what is solid requires two means, because it not only has breadth but also depth, God has placed air and water between fire and earth; and indeed He gave to them the same proportion, so that fire is related to air as air to water, and as air is to water, so is water to earth.”[49] Thus we have, properly speaking, four methods of representing space, inasmuch as the point is, through line and surface, closely bound up with the solid body. The sundered mean here discovered, again indicates an important thought of logical profundity; and the number four which here appears, is in nature a fundamental number. For as being the different which is turned towards the two extremes, the mean must be separated in itself. In the conclusion in which God is the One, the second (the mediating), the Son; the third, the Spirit; the mean indeed is simple. But the cause why that which in the rational conclusion is merely three-fold, passes in nature to the four-fold, rests in what is natural, because what in thought is immediately the one, becomes separate in Nature. But in order that in Nature the opposition should exist as opposition, it must itself be a twofold, and thus, when we count, we have four. This also takes place in the conception of God, for when we apply it to the world, we have nature as mean and the existent spirit as the way of return for nature: when the return is made, this is the absolute Spirit. This living process, this separation and unifying of differences, is the living God. Plato says further: “Through this unity the visible and tangible world has been made. And it comes to pass by God’s having given to it these elements entire and unseparated, that it is perfect, and unaffected by age and disease. For old age and disease only arise from a body’s being worked upon by a superabundance of such elements from without. But here this is not so, for the world contains those elements entirely in itself, and nothing can come to it from without. The world is spherical in form,” (as it was to Parmenides and the Pythagoreans) “as being most perfect, and as containing all others in itself; it is perfectly smooth, since for it there is nothing outside, and it requires no limbs.” Finitude consists in this, that a distinction as regards something else is an externality to some other object. In the Idea we certainly have determination, limitation, difference, other-being, but it is at the same time dissolved, contained, gathered together, in the one. Thus it is a difference through which no finitude arises, seeing that it likewise is sublated. Finitude is thus in the infinite itself, and this is, indeed, a great thought. “God gave the world the most appropriate motion of all the seven, being that which harmonizes best with mind and consciousness, motion in a circle; the other six He took away from it and liberated it from their variations”[50] (movements backwards and forwards). This is only a popular way of putting it.