Anselm’s ontological argument, sourced from the “Proslogium” (with himself as the author), is a highly controversial argument that aims to prove the existence of God. This argument is an attempt of an a priori proof, that which uses purely uses intuition and reasoning alone (Oppy G. 1996). The argument (simplified) is as follows:
One can imagine a being than which none greater can be conceived. We know that existence in reality is greater than existence in the mind alone. If the being we imagine exists only in our mind, then it is not a “being than which none greater can be conceived”. A being than which none greater can be conceived must also exist in reality. Failure to exists in reality would be failure to be a being than which none greater can be conceived. Thus a being than which none greater can be conceived must exist, and we call this being God.
It is good to note, while tackling this argument, Anselm’s point of view in developing his argument. First, this, (the Proslogium in general), was written from a Christian perspective, wherein the author may have some form of ‘presupposed bias’ (for lack of a better term) towards the existence of the being in question. Second, the author’s intention for developing such an argument was not for the purpose of convincing non-Christians of the truth of his beliefs, but rather for the purpose of existing believers seeking rationale for his or her faith (Deane S. 1962).
It is unsurprising that this argument is highly controversial and receives as much criticism as it had and still does. Many philosophers including St. Thomas...