God and Man
Having, in the first part, discoursed on God, and on the universal and infinite things, we shall proceed now, in the second part, to the treatment of particular and finite things; though not of all, since they are innumerable, but we shall only treat of those which concern man; and, in the first place, we shall consider here what man is, in so far as he consists of certain modes (contained in the two attributes, things and ideas, which we have remarked in God). I say of certain modes, for I by no means think that man, in so far as he consists of spirit, soul, or body, is a real substance. Because, already at the beginning of this book, we proved (1) that no real substance can have a beginning; (2) that one substance cannot produce another; and lastly (3), that there cannot be two like substances.
As man has not been in existence from eternity, is finite, and is like many men, he can be no real substance; so that all that he has of thought are only modes of the attribute thought which we have attributed to God. And, again, all that he has of form, motion, and other things, are likewise [modes] of the other attribute which is attributed by us to God.
And although from this, [namely,] that the nature of man can neither be, nor be understood without the attributes which we ourselves admit to constitute substance, some try to prove that man is a substance, yet this has no other ground than false supposition. For, since the nature of matter or body existed before the form of this human body existed, that nature cannot be peculiar to the human body, because it is clear that during the time when man was not, it could never belong to the nature of man.
And what they set up as a fundamental principle, [namely,] that that pertains to the nature of a thing, without which the thing can neither be, nor be understood, we deny. For we have already shown that without God no thing can be or be understood. That is, God must first be and be understood before these particular things can be and be understood. We have also shown that genera do not belong to the nature of definition, but that only such things as cannot exist without others, can also not be understood without these. This being so, what kind of a rule shall we, then, state, whereby it shall be known what belongs to the nature of a thing?
Well, the rule is this: That belongs to the nature of a thing, without which the thing can neither be, nor be understood; not merely so, however, but in such wise that the judgment must be convertible, that is, that the predicate can neither be, nor be understood without the thing. Of these modes, then, of which man consists, we shall begin to treat at the commencement of the following first chapter.