Philosophy 272: Handout Le1

Leibniz' Proofs for the Existence of God

Cosmological (Monadology 36-37, Principles of Nature and Grace 8)

1. There is a sufficient reason for the series of contingent things, i.e. the universe.
2. The sufficient reason cannot be found internal to the series of contingent things (even if the series is infinite).
3. Hence, the sufficient reason lies outside the series (even if the series is infinite).
4. The only thing that could lie outside the series of contingent things is a necessary being.
5. Hence, the sufficient reason must be a necessary being, i.e. God.

Ontological (Discourse on Metaphysics 23)

1. The idea of God is of a being with all perfections.
2. Necessary existence is perfection.
3. Hence, the idea of God is of a being with necessary existence.
4. If the idea is both of a possible being and of a being with necessary existence, then the being exists.
5. The idea of God is of a possible being.
6. Hence, God exists.

Pre-established Harmony (New System 16)

1. There are simple substances.
2. The apparent interaction between mind and between minds and bodies can only be explained in terms of a pre-established harmony.
3. The pre-established harmony is so complex, that only God could be its author.
4. Hence, God exists.

Eternal Truths (Monadology 43-46)

1. There is reality among essences, possibilities, or eternal truths.
2. If there is reality among essences, possibilities or eternal truths, that reality must be grounded in something existent.
3. Whatever grounds the reality of essences, possibilities, or eternal truths cannot be a contingent being.
4. Hence, a necessary being, i.e. God, exists who grounds the reality among essences, possibilities or eternal truths.