The notion of the infinite and the perfect is for Descartes what the universal, the Idea, is for Plato. No sooner has Descartes found by consciousness that he thinks, than he concludes from this that he exists, then, in course, by consciousness still, he recognizes himself as imperfect, full of defects, limitations, miseries, and, at the same time, conceives something infinite and perfect. He possesses the idea of the infinite and the perfect; but this idea is not his own work, for he is imperfect; it must then have been put into him by another being endowed with perfection, whom he conceives, whom he does not possess:--that being is God. Such is the process by which Descartes, setting out from his own thought, and his own being, elevated himself to God. This process, so simple, which he so simply exposes in the _Discours de la Methode_, he will put successively, in the _Meditations_, in the _Responses aux Objections_, in the _Principes_, under the most diverse forms, he will accommodate it, if it is necessary, to the language of the schools, in order that it may penetrate into them. After all, this process is compelled to conclude, from the idea of the infinite and the perfect, in the existence of a cause of this idea, adequate, at least, to the idea itself, that is to say, infinite and perfect. One sees that the first difference between Plato and Descartes is, that the ideas which in Plato are at once conceptions of our mind, and the principles of things, are for Descartes, as well as for all modern philosophy, only our conceptions, amongst which that of the infinite and perfect occupies the first place; the second difference is, that Plato goes from ideas to God by the principle of substances, if we may be allowed to use this technical language of modern philosophy; whilst Descartes employs rather the principle of causality, and concludes--well understood without syllogism--from the idea of the infinite and the perfect in a cause also perfect and infinite.[58] But under these differences, and in spite of many more, is a common basis, a genius the same, which at first elevates us above the senses, and, by the intermediary of marvellous ideas that are incontestably in us, bears us towards him who alone can be their substance, who is the infinite and perfect author of our idea of infinity and perfection. For this reason, Descartes belongs to the family of Plato and Socrates. The idea of the perfect and the finite being once introduced into the philosophy of the seventeenth century, it becomes there for the successors of Descartes what the theory of ideas became for the successors of Plato.