Propositions 1 to 8

Postulates

1. The human body can be affected in many ways which increases or reduces its power of activity.
2. It can also be affected in other ways which do not change this power.

Note: This postulate or axiom rests on Postulate 1 and Lemmas 5 and 7, which is after 2.13.

The human body can undergo many changes.

Nevertheless, it can retain:

• the impressions or traces of objects (cf. 2. Post. 5) and
• consequently, the same images of things (see note 2.17).

Propositions

1. Our mind is active in certain cases, and passive in certain cases.

• It is active in so far as it has adequate ideas.
• It is passive in so far as it has inadequate ideas.

Proof: In every human mind, there are some adequate ideas, and some ideas that are fragmentary and confused (2. 40. note).

The ideas which are adequate in the mind are adequate also in God, as he constitutes the essence of the mind (2.40. Coroll.).

Corollary: It follows that the mind is more or less liable to be acted upon, as it has inadequate ideas. On the contrary, it is more or less active in proportion as it has adequate ideas.

2. The body cannot determine the mind to think. The mind cannot determine body to motion or rest or any state different from these, if such there be.

Proof: God is the cause of all modes of thinking, by virtue of his being a thinking thing, and not by virtue of his being displayed under any other attribute (2.6). That, therefore, which determines the mind to thought is a mode of thought, and not a mode of extension. That is (2 Def. 1), it is not body.

3. The mind’s activities arise solely from adequate ideas. The mind’s passive states depend solely on inadequate ideas.

4. Nothing can be destroyed, except by a cause external to itself.

5. Things are naturally contrary, that is, cannot exist in the same object, in so far as one is capable of destroying the other.

6. Everything in itself endeavours to persist in its own being.

7. The endeavour, wherewith everything endeavours to persist in its own being, is nothing else but the actual essence of the thing in question.

8. The endeavour, whereby a thing endeavours to persist in its own being, involves no finite time, but an indefinite time.