The Collected Works of Benedict de Spinoza

For those who begin to philosophize from the mind itself, it is permitted to fix one's attention on what is within us, or rather what we ourselves are, and to contemplate it, as it were, from close up, from within. From there, one must proceed from the certain, attempting to build firm foundations with cautious reasoning. For nothing at all can be more certain to us who think than this very "Being" of ours. Nor can any other measure of certainty be thought of as tractable to us, as humans, than this: whether something exists within our "Being," and whether it could be denied only if this were denied, such that those things that stand and fall with our necessary "Being" deserve to be called true, while those things that rely only on accidents in this "Being of ours" and are equal to them are merely "truth-like" likely true, but not certain.. On the other hand, if they institute the path of philosophizing from the Infinite, they cannot deny that they are proceeding from a mystery that is for the most part inscrutable, just as Spinoza himself understands God as a substance consisting of infinite attributes (Ethics, Def. VII), of which he seemed to himself to have knowledge of only two, namely that it is thinking and extended (Ethics, Part II, Prop. 1, 2). And these very two attributes, through which he professed to have as clear an idea of God as he did of a triangle (Epist. LX, p. 659, Vol. I)—from where could he finally have had true knowledge of them? If he had not considered his own mind before all else, he could have had neither the concept of thinking nor...