1. By a thing which is causa sui, its own cause, I mean a
thing the essence of which involves the existence of it, or a
thing which cannot be conceived of except as existing.
2. I call a thing finite, suo genere, when it can be
circumscribed by another (or others) of the same nature, e.g.
a given body is called finite, because we can always conceive
another body larger than it; but body is not circumscribed
by thought, nor thought by body.
3. By substance I mean what exists in itself and is conceived
of by itself; the conception of which, that is, does
not involve the conception of anything else as the cause
of it.
4. By attribute I mean whatever the intellect perceives of
substance as constituting the essence of substance.
5. Mode is an affection of substance, or is that which is
in something else, by and through which it is conceived.
6. God is a being absolutely infinite; a substance consisting
of infinite attributes, each of which expresses His
eternal and infinite essence.