Criticism of Gaunilo's perfect island?
Anselm defines god as a being than which nothing greater can be conceived (defined purely in terms of greatness), and further argues that it is greater to exist in both the imagination and reality as proof of gods existence
Gaunilo argues ad absurdum that a perfect island must really exist too, following Anselm's logic. However, an island is already defined by, for example, being a body of land, being surrounded by water, etc. Could the property of "being a property of land" be maximally great to the fullest extent, i.e matching God? Arguably, the island is restricted in it's maximum greatness as it is not defined purely in terms of greatness, as God is to Anselm, instead it is defined in other ways which limit it - for example, if I were to have a fear of the ocean, an island wouldn't be very great would it? What if I even were to have an irrational fear of islands themselves?