The Stoic philosopher Cleanthes, author of the famous Hymn to Zeus, argued that every comparison, in affirming or denying one thing to be better than another, implied and presupposed the existence of a superlative or an absolutely good and perfect Being. Centuries later, Boethius had recourse to nearly identical reasoning. It is only, he maintained, through the idea of perfection that we can judge anything to be imperfect; and the consciousness or perception of imperfection leads reason necessarily to believe that there is a perfect existence--one than whom a better cannot be conceived--God. Cleanthes and Boethius were thus the precursors of Anselm, who was, however, the first to endeavour to show that from the very idea of God as the highest Being His necessary reality may be strictly deduced. In consequence, Anselm was the founder of that kind of argumentation which, in the opinion of many, is alone entitled to be described as _a priori_ or ontological. He reasoned thus: "The fool may say in his heart, There is no God; but he only proves thereby that he is a fool, for what he says is self-contradictory. Since he denies that there is a God, he has in his mind the idea of God, and that idea implies the existence of God, for it is the idea of a Being than which a higher cannot be conceived. That than which a higher cannot be conceived cannot exist merely as an idea, because what exists merely as an idea is inferior to what exists in reality as well as in idea. The idea of a highest Being which exists merely in thought, is the idea of a highest Being which is not the highest even in thought, but inferior to a highest Being which exists in fact as well as in thought." This reasoning found unfavourable critics even among the contemporaries of Anselm, and has commended itself completely to few. Yet it may fairly be doubted whether it has been conclusively refuted, and some of the objections most frequently urged against it are certainly inadmissible. It is no answer to it, for example, to deny that the idea of God is innate or universal. The argument merely assumes that he who denies that there is a God must have an idea of God. There is also no force, as Anselm showed, in the objection of Gaunilo, that the existence of God can no more be inferred from the idea of a perfect being, than the existence of a perfect island is to be inferred from the idea of such an island. There neither is nor can be an idea of an island which is greater and better than any other that can ever be conceived. Anselm could safely promise that he would make Gaunilo a present of such an island when he had really imagined it. Only one being--an infinite, independent, necessary being--can be perfect in the sense of being greater and better than every other conceivable being. The objection that the ideal can never logically yield the real--that the transition from thought to fact must be in every instance illegitimate--is merely an assertion that the argument is fallacious.