The ontological argument is unquestionably one of the most interesting arguments for the existence of God. Similar to all ontological arguments is that the concept of God entails that there exists in reality a being which corresponds to this definition, or more simply: God exists. Any perusal of the philosophical literature will show that the ontological argument is still very much debated in different forms. I will show that the ontological argument does not succeed in what it tries to do, namely, prove that God exists. I will consider the first form of Anselm’s original argument, Descartes’ argument, Hartshorne’s, and that of Plantinga.
Anselm first gave what has become known as the ontological argument in his Prosologion. He used the definition that God is that being than which no greater can be conceived. Using this, he gave a reductio ad absurdum, that if one claimed that this being did not exist, then there exists a being which is greater than the being which no greater can be conceived. A major assumption of Anselm’s was that whatever exists in both the mind and in reality is greater than that which exists only in the mind. However, it is tough to see why one should accept this premise as sound. Is five dollars actually being in my pocket greater than 100 dollars existing in my mind? Can we even make such a comparison? This does not seem likely. One cannot claim that an old worn down coin is greater than a hypothetical brand new one of the same date, just because it exists. Furthermore, the premise that if one denies the existence of God, that there is a being greater than the being which no greater can be conceived, presupposes the actual existence of that being, so the argument runs in a circle. Hence, Anselm’s original argument fails.
Descartes’ ontological argument is simpler than Anselm’s, but unfortunately is more question-begging also. His argument is:
- God contains all perfections.
- Existence is a perfection.
- Therefore, God contains existence (or God exists.)
The second premise is highly questionable at best. Generally, one would think that bringing something into in existence would cause an imperfection in the object; one does not see how at first why God would be any different. For example, if one thinks of a perfect hill (such as the one just outside of Buchanon VA), the conception of the hill would be more perfect than a hill in existence; hence bringing something into existence does not make it more perfect, and therefore existence is not a perfection. So Descartes argument also fails.
Hartshorne’s ontological argument is based on Anselm’s second argument and claims that God’s existence is logically necessary. Hartshorne’s argument is given here, where