human mind can only acquire knowledge of those things which the idea of a body actually existing involves, or of what can be inferred from such an idea. For the power of anything is defined solely by its essence (Ethics, E3P7); the essence of the mind (Ethics, E2P13) consists solely in this, that it is the idea of body actually existing; therefore the mind's power of understanding only extends to things, which this idea of body contains in itself, or which follow therefrom. Now this idea of body does not involve or express any of God's attributes, save extension and thought. For its object (ideatum), namely, body (by Ethics, E2P6), has God for its cause, in so far as He is regarded under the attribute of extension, and not in so far as He is regarded under any other; therefore (Ethics, E1A6) this idea of the body involves the knowledge of God, only in so far as He is regarded under the attribute of extension. Further, this idea, in so far as it is a mode of thinking, has also (by the same proposition) God for its cause, in so far as He is regarded as a thinking thing, and not in so far as He is regarded under any other attribute. Hence (by the same axiom) the idea of this idea involves the knowledge of God, in so far as He is regarded under the attribute of thought, and not in so far as He is regarded under any [other] attribute. It is therefore plain, that the human mind, or the idea of the human body neither involves nor expresses any attributes of God save these two. Now from these two attributes, or their modifications, no other attribute of God can (Ethics, E1P10) be inferred or conceived. I therefore conclude, that the human mind cannot attain knowledge of any attribute of God besides these, which is the proposition you inquire about. With regard to your question, whether there must be as many worlds as there are attributes, I refer you to Ethics E2P7CN note.
essence and existence; for things which differ to this extent seem to have nothing in common. But since all particular things, except those which are produced from things similar to themselves, differ from their causes both in essence and existence, I see here no reason for doubt.
God is the efficient cause of things, no less of their essence than of their existence, I think has been sufficiently explained in Ethics E1P25N and E1P25C. The axiom in the note to Ethics E1P10N, as I hinted at the end of the said note, is based on the idea which we have of a Being absolutely infinite, not on the fact, that there are or may be beings possessing three, four, or more attributes.
infinite understanding; in extension, motion and rest; an example of the second kind is the sum of the whole extended universe (facies totius universi), which, though it varies in infinite modes, yet remains always the same. Cf. Ethics E2P13L7N.
The Hague, 29 July, 1675.