His works are short, but weighty. Of his important treatises, the one, the _Tractatus Theologico-Politicus_, shows him as the Biblical critic; the other, the _Ethica_, exhibits his philosophy. In the former, written in early life, he derives his materials and mode of handling from the Jewish mediæval theologian Maimonides; in the latter, the product of his riper years, from Descartes.(335) But he had undoubtedly come under the influence of Descartes before writing the former work, and it is certain that the effects of it on his own philosophical scheme are already discernible in it. We shall therefore commence with the latter, and attempt to understand his philosophy, and its application to religion, before studying his special criticism of Revelation. Descartes had aimed, like the great thinkers of earlier times, to gain a general view of the universe of being; but had sought it by a different mode. Caring rather for certitude of method, reality in the highest principles, than for results attained, he had seen that a knowledge of being must rest on a knowledge of the consciousness which tells us of being. His principle, “Cogito, ergo sum,” is the expression of this conviction. Therefore, carrying analysis into the human mind, he had grasped those ideas which appeal to us with irresistible clearness, and commend themselves as axioms requiring no proof; and from these ideas, or rather from the idea of cause, the primitive of them, regarded by him as innate, he had demonstrated _à priori_ the being and attributes of God, and the principles which dominate in the great fields of knowledge.(336)