In chapter ten, The Ontological Argument, Groothius states that the ontological argument claims that proper reasoning about the idea of a Perfect Being generates the conclusion that God exists. St. Anselm (c. 1033-1109) created this argument to convince the fool or atheist in Psalm 14:1 as to the existence of God and to lead believers in the worship of the greatest possible being in the following prayer:
Therefore, 0 Lord, you who give understanding to faith, grant me to understand to the degree You know to be advantageous that You exist, as we believe, and that You are what we believe [You to be]. Indeed, we believe You to be something than which nothing greater can be thought. Or is there, then, no such nature [as You], for the Fool has said in his heart that God does not exist? But surely when this very same Fool hears my words “something than which nothing greater can be thought,” he understands what he hears. And what he understands is in his understanding, even if he does not understand [i.e., judge] it to exist. For that a thing is in the understanding is distinct from understanding that [this] thing exists. For example, when a painter envisions what he is about to paint: he indeed has in his understanding that which he has not yet made, but he does not yet understand that it exists. But after he has painted [it]: he has in his understanding that which he has made, and he understands that it exists. So even the Fool is convinced that something than which nothing greater can be thought is at least in his understanding; for when he hears of this [being], he understands [what he hears], and whatever is understood is in the understanding. But surely that than which a greater cannot be thought cannot be only in the understanding. For if it were only in the understanding, it could be thought to exist also in reality something which is greater [than existing only in understanding]. Therefore, if that than which a greater cannot be thought were only in the understanding, then that than which a greater cannot be thought would be that than which a greater can be thought! But surely this [conclusion] is impossible. Hence, without doubt, something than which a greater cannot be thought exists both in the understanding and in reality (Proslogiume 2).
Actually, he created two ontological arguments.
The first argument:
1) The idea of a Perfect Being is conceivable.
2) Existence can function as a predicate or attribute for God.
3) It is better for a Perfect Being to exist than not to exist.
An argument for the existence of God that argues from the idea of God itself to the reality of God. It was attributed first to Anselm and later to Descartes, who declared that because God is by definition "the most perfect being," God must exist; otherwise God would lack one perfection, namely, existence (Stanley J. Grenz, David Guretzki, and Cherith Fee Nordling, Pocket Dictionary of Theological Terms, 86).
The second argument adds the idea of necessary to the Perfect Being:
1) God is defined as a maximally great or Perfect Being.
2) The existence of a Perfect Being is either impossible or necessary.
3) The concept of a Perfect Being is not impossible, since it is neither nonsensical nor self-contradictory.
4) Therefore (a) a Perfect Being is necessary.
5) Therefore (b) a Perfect Being exists.
I am going to fall back on Blaise Pascal’s argument against theistic arguments: they are too complex to be helpful.
Here is a syllogism for the ontological argument:
Major premise: The human mind possesses the idea of an absolutely perfect being
Minor premise: Absolute perfection of being implies necessity of existence (for that which must exist is of a higher order than that which may exist)
Conclusion: An absolutely perfect being does exist---for that which must exist, does exist (Alan Cairns, Dictionary of Theological Terms, p. 38).
Robert Reymond, however, rejects the ontological argument. As a prayer this argument presupposes the existence of Anselm's God but, as has been often noted, this argument as pure argument at best only proves that people are incapable of holding the concept of a perfect God in the mind that does not include his existence in reality. But their concept of God existing in reality and the actual existence of such a God are not the same: the former no more establishes the objective reality of its corresponding entity than a merchant's writing zeroes in his ledger increases his actual wealth (so Kant).
Gaunilo, the 11th century monk, tried also to refute the ontological argument by using a perfect island instead of a Perfect Being.
Gaunilo's parody runs along the same lines:
- The Lost Island is that island than which no greater can be conceived.
- It is greater to exist in reality than merely as an idea.
- If the Lost Island does not exist, one can conceive of an even greater island, that is one that does exist.
- Therefore, the Lost Island exists in reality.
Groothius answers this argument by stating "an island, by definition, is not a necessary being....what makes the ontological argument work is the ontology of God as a necessary being. Anything that is less than God necessarily lacks this ontology (set of properties) and so cannot be the subject of an ontological argument. Therefore, this parallel/parody argument fails."