The Existence of God
For being accustomed in all other things to make a distinction between existence and essence, I easily persuade myself that existence may perhaps be separated from the essence of God, and thus God might be conceived as not existent actually. PROP. XI. God, or substance, consisting, of infinite attributes, of which each expresses eternal and infinite essentiality, necessarily exists.
"Proof.--If this be denied, conceive, if possible, that God does not exist: then his essence does not involve existence. --Of everything whatsoever a cause or reason must be assigned, either for its existence, or for its non-existence --e. g., if a triangle exist, a reason or cause must be granted for its existence; if, on the contrary, it does not exist, a cause must also be granted, which prevents it from existing, or annuls its existence. "If, then, no cause or reason can be given, which prevents the existence of God, or which destroys his existence, we must certainly conclude that he necessarily does exist. For if it were of the same nature, God, by that very fact, would be admitted to exist. But substance of another nature could have nothing in common with God (by Prop. ii.), and therefore would be unable either to cause or to destroy his existence.
"As, then, a reason or cause which would annul the divine existence cannot be drawn from anything external to the divine nature, such cause must perforce, if God does not exist, be drawn from God's own nature, which would involve a contradiction. To make such an affirmation about a being absolutely infinite and supremely perfect, is absurd; therefore, neither in the nature of God, nor externally to his nature, can a cause or reason be assigned which would annul his existence. Therefore, God necessarily exists. --The potentiality of non-existence is a negation of power, and contrariwise the potentiality of existence is a power, as is obvious. --In this last proof, I have purposely shown God's existence a posteriori, so that the proof might be more easily followed, not because, from the same premises, God's existence does not follow a priori. Imperfection, on the other hand, does annul it; therefore we cannot be more certain of the existence of anything, than of the existence of a being absolutely infinite or perfect --that is, of God. "Our idea of a most perfect being, not the sole proof of a God. --How far the idea of a most perfect being which a man may frame in his mind, does or does not prove the existence of a God, I will not here examine.