Arguments for the Existence of God

Although many people—believers and atheists alike—argue the existence of God, it cannot be proven. Philosophers since Aristotle have tried to do so. There are three kinds of argument for the existence of God. The first is called ontological, and it goes back to the medieval philosopher Saint Anselm of Canterbury (1033–1109). Saint Anselm’s own theory was more complicated, but the basic outline of the ontological argument is as follows:

God is the most perfect possible being. (Definition)
It is more perfect to exist, than not to exist.
If God did not exist, then God would lack a perfect existence. (From ii)
Therefore, God exists. (From i and ii)

The second kind of argument for God’s existence is the cosmological. The basic form of the cosmological argument is to argue that there must be a first cause of everything that exists, a cause which is itself not caused. This first cause must be God, because nothing but God could exist without being caused. A variation on the cosmological argument is the argument that everything except God is contingent, in other words, it is possible for everything else not to exist. But every contingent thing requires a cause that is itself necessary. This necessary cause is God.

The third kind of argument is the argument from design. Not as logically strict as the other two, this argument asserts that the world has features that are best explained by the hypothesis that it was created by an intelligent designer. Features of the world often cited include the harmony among its physical laws that make life possible, the adaptation of organisms to their environments, and the fact that human beings are intelligent, self-conscious beings.


  1. Since Charles Darwin (1809–1882), many philosophers—but not all— have insisted the argument from design does not work because every feature of the world is adequately explained by science, especially evolution

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