This continues the series of weekly posts dealing with some basic theistic arguments. The purpose here is to introduce the reader to the idea behind each argument. Strengths and weaknesses will be presented after each summary. These are only summaries and springboards for further study in the theistic arguments. See Reason for the Hope Within for more.
An Argument from the Definition of God and the Superiority of Existing in Reality
Anselm defined God as that being than which no greater can be conceived, and further assumed that it is greater to exist in reality than it is to exist only in the mind (as a thought). But given these two premises, the supposition that God exists only in the mind can’t possibly be true: the greatest conceivable being can’t exist only in the mind because we can conceive of that same being existing in reality as well. A greatest conceivable being (God) which exists in the mind is contradictory. Thus, God must exist in reality.
Greatest Strength: The argument requires accepting only a definition and the claim that to exist is better than not.
Greatest Weakness: It feels like a trick, even if it is hard to say why. One likely source: widespread misgivings about deriving existence from a definition.1
1 William C. Davis, Reason for the Hope Within (Grand Rapids, MI: Eerdman’s Publishing Co., 1999), p. 30.