Everybody has heard that God is love and that love makes the world go round; and those who have traced this latter notion back to its source in Aristotle may have some notion of what it means. It means, as we saw in the beginning, that we should not try to explain motion and life by their natural antecedents, for these run back _in infinitum_. We should explain motion and life rather by their purpose or end, by that unrealized ideal which moving and living things seem to aspire to, and may be said to love. What justifies itself is not any fact or law; for why should these not have been different? What justifies itself is what is good, what is as it ought to be. But things in motion, Aristotle conceived, declare, as it were, that they are not satisfied, and ought to be in some different condition. They look to a fulfilment which is as yet ideal. This fulfilment, if it included motion and life, could include them inwardly only; it would consist in a sustained activity, never lapsing nor suffering change. Such an activity is the unchanging goal towards which life advances and by which its different stages are measured: But since the purpose of things, and not their natural causes, is that which explains them, we may call this eventual activity their reason for being. It will be their unmoved mover. But how, we may ask,--how can the unchanging, the ideal, the eventual, initiate anything or determine the disposition and tendency of what actually lives and moves? The answer, or rather the impossibility of giving an answer, may be expressed in a single word: magic. It is magic when a good or interesting result, because it would prove good or interesting, is credited with marshalling the conditions and evoking the beings that are to realize it. It is natural that I should be hungry, and natural that there should be things suitable for me to eat--for otherwise I should not be hungry long; but if my hunger, in case it is sharp enough, should be able of itself to produce the food it calls for, that would be magic. Nature would be evoked by the incantations of the will.