Therefore this idea of God which is in us demands God for its cause, and consequently God exists (by Axiom III ).
Proposition III
The existence of God is also demonstrated from this, that we ourselves, who possess the idea of him, exist.
Demonstration
If I possessed the power of conserving myself, I should likewise have the power of conferring, a fortiori , on myself, all the perfections that are awanting to me (by Axioms VIII and IX ), for these perfections are only attributes of substance, whereas I myself am a substance.
But I have not the power of conferring on myself these perfections, for otherwise I should already possess them (by Axiom VII ).
Hence, I have not the power of self-conservation.
Further, I cannot exist without being conserved, so long as I exist, either by myself, supposing I possess the power, or by another who has this power (by Axioms I and II ).
But I exist, and yet I have not the power of self-conservation, as I have recently proved. Hence I am conserved by another.
Further, that by which I am conserved has in itself formally or eminently all that is in me (by Axiom IV ).
But I have in me the perception of many perfections that are awanting to me, and that also of the idea of God (by Definitions II and VIII ). Hence the perception of these same perfections is in him by whom I am conserved.