By Ryan Hemelaar
Where would an archive of the 'Proofs for God' be without the good old ontological argument? St Anselm developed the argument in 1074 and it can be summarised as follows:
- God is, by definition, a being greater than anything that can be imagined.
- To exist in reality is greater than to solely exist in one's imagination.
- Therefore, God must exist in reality: if He did not, He would not be a being greater than anything that can be imagined.
Soon after developing his argument, Gaunilo objected to it because he said if someone thinks of the greatest conceivable island, that too must exist. However, Gaunilo's example of the greatest conceivable island is not equivalent, as Alvin Platinga points out:
No matter how great an island is, no matter how many Nubian maidens and dancing girls adorn it, there could always be a greater — one with twice as many, for instance. The qualities that make for greatness in islands — number of palm trees, amount and quality of coconuts, for example — most of these qualities have no intrinsic maximum. That is, there is no degree of productivity or number of palm trees (or of dancing girls) such that it is impossible that an island display more of that quality. So the idea of the greatest possible island is an inconsistent or incoherent idea; it's not possible that there be such a thing.[1]
Over the centuries there has been many objections to Anselm's argument, yet no conclusive defeater has been found. That is why Anselm's argument lives on even to this very day.
But there have been other ontological arguments developed throughout the centuries, one of which bases itself on modal logic, such as below:
1. It is possible that a maximally great being exists.
2. If it is possible that a maximally great being exists, then a maximally great being exists in some possible world.
3. To have necessary existence is greater than to have contingent existence.
4. If a maximally great being exists in some possible world, then it exists in every possible world.
4a. If a maximally great being exists only in some possible worlds and not all possible worlds, then the maximally great being's existence is contingent.
4b. A maximally great being however cannot be both necessary and contingent in their existence (law of non-contradiction).
5. If a maximally great being exists in every possible world, then it exists in the actual world.
6. Therefore, a maximally great being exists.
A possible world does not refer to a planet or even a universe, but rather to a way reality might be.
It might surprise you to learn that premises 2-6 of this argument are relatively uncontroversial[2]. Most philosophers would agree that if God's existence is even possible, then he must exist. So the whole question is: Is God's existence possible? The atheist has to maintain that it's impossible that God exists. He has to say that the concept of God is incoherent, like the concept of a married bachelor or a round square. But the problem is that the concept of God just doesn't appear to be incoherent in that way. The idea of a being which is all-powerful, allknowing, and all-good in every possible world seems perfectly coherent. And so long as God's existence is even possible, it follows that God must exist.
[1] Platinga, A. (Grand Rapids: Eerdmans, 1974) God, Freedom and Evil, p. 90 – 91.
[2] Craig, W. (Illinois: Crossway, 2008) Reasonable Faith, p. 185.
