=Deduction――The Implications of Consciousness.= For Descartes reality lies within the Self; and the next question before him is how to get out of the Self. Knowledge that is confined to the Self and its states is called, technically, solipsism. Such knowledge amounts to little; indeed, it is not knowledge at all. Certainty of self-existence is the minimum amount of knowledge――merely the starting point of knowledge. Descartes proposes to escape from this solipsism by the use of logic. His method from this point on is ostensibly deductive, although he introduces by the side door other ideas than the idea of Self to make his proof complete. Descartes maintains that any idea will be as true as the consciousness that accompanies it, just as a proposition in geometry partakes of the truth of the axioms from which it is derived. Now my consciousness contains many ideas; some of them seem to be the product of my imagination; some seem to be adventitious; some are innate. It is upon the innate ideas that Descartes depends to get him out of his solipsism, for they are not created by the Self and they have the qualities of truth――a conscious clearness and distinctness. Among these innate ideas is the idea of God as a perfect being. =The Existence of God.[28]= As a deduction from consciousness, the idea of God would prove to be a very useful one to Descartes, provided it had reality. For it is evident that consciousness can testify only to the existence of itself and its own states. How do I know the reality of anything else? Am I confined within the circle of my own thinking? Is all that I can say of this or that, “It is real to me”? Are all things only the phantasmagoria of my own brain, testifying only to the existence of myself? Descartes thought that the idea of God relieved him of this solipsism. If he could demonstrate God’s existence, he would then be able to demonstrate the existence of the material universe. The problem was so highly important to Descartes that he threw it into several different arguments. The complications with which these arguments are filled must be passed over here, and the arguments stated in their simplest forms. (a) Two are ontological arguments, that is, arguments from the character of the conception of God’s nature. (1) _A Simple Deduction._ If I have in my consciousness any idea as clear and distinct as my idea of Myself, it must have existence like Myself. My idea of God has just that clearness and distinctness; and therefore God exists. (2) _The Geometrical Argument_, so called by Descartes. Some ideas have properties so immutable that, when we think the ideas, we necessarily think their properties. Such is the idea of a triangle; when I think of a triangle, I must think of it as having its three angles equal to two right angles. Such is also my idea of God; I must think of him as perfect and existing. He would not be God, _i. e._ a perfect Being, if He did not exist.