vi.) the cause, why the mind affirms the existence of the body, is not that the body began to exist; therefore, for the same reason, it does not cease to affirm the existence of the body, because the body ceases to exist; but (II.

xvii.) this result follows from another idea, which excludes the present existence of our body and, consequently, of our mind, and which is therefore contrary to the idea constituting the essence of our mind.
PROP.XII.

The mind, as far as it can, endeavours to conceive those things, which increase or help the power of activity in the body.
Proof .-- So long as the human body is affected in a mode, which involves the nature of any external body, the human mind will regard that external body as present (II.

xvii.), and consequently (II.

vii.), so long as the human mind regards an external body as present, that is (II.xvii.