The Ontological Argument is an attempt to prove God’s existence by purely logical means. It claims the definition of God is so intimately connected with His existence that as soon as you understand what God is, you know He exists. There have been many formulations of the Ontological Argument. The most famous belongs to Saint Anselm of Canterbury, whose argument I will (heavily) paraphrase below.
The Ontological Argument goes roughly like this:
- God is the greatest thing; nothing can be thought of which is greater than Him
- What is understood exists in the mind, even if it does not exist in reality
- Everyone understands what is meant by ‘the greatest thing’, even if they do not call it God
- Therefore, the concept of God exists in the minds of everyone
- If God exists in the mind, He must also exist in reality
- It is greater to exist both in the mind and in reality than it is to exist only in the mind
- If God existed only in the mind, it would be possible to think of something greater than God (namely, a God which also existed)
- It is impossible to think of something greater than God
- Therefore, God cannot exist only in the mind
- Since God exists in the mind (of everyone), and He cannot exist in the mind alone, He must also exist in reality.
So, God exists. Convinced?
Probably not. There are two species of problems with the Ontological Argument. First, it is conspicuously unappealing. It conjures the supreme being into existence by semantic trickery. Second, there are a number of logical problems with the argument.
Over the years, several philosophers have attacked the Ontological Argument on various grounds. Anselm’s contemporary, Guanilo of Marmoutiers, attacked the Argument with reductio ad absurdum; he used the Ontological Argument to ‘prove’ the existence of the ‘best island’. This island would be the greatest island, and since it is better to exist in reality, it must exist in reality. Not seeing any ‘best island,’ Guanilo concluded the Ontological Argument was flawed. Centuries later, Immanuel Kant challenged Anselm’s premise that existence is a perfection, that existing in reality is an improvement over a mere concept. Kant argued that you do not add anything to the concept of a thing by adding ‘and it also exists’. If existence is not a perfection, the Ontological Argument collapses.
But even if the Ontological Argument were unassailably true, it only proves there is a being which is the greatest in every way; it does not prove this being corresponds to any one god worshipped by any one religion. At best, it can reassure theists there is a destination at the end of the journey; what path to take is an open question.