The issue I want to address is the so-called Ontological Argument for the existence of God as first proposed by St. Anselm almost a thousand yeasrs go and further developed and promoted by Muslim and Christian philosophers, including relatively recent versions by Alvin Plantinga, Kurt Gödel and others.
I was asked to write about this some time ago by a fellow commenter on Massimo Pigliucci's (now no longer active) blog 'Rationally Speaking', and I said I would. However I have been slow to do so for a couple of reasons (in addition to the usual procrastination!). The first is that the argument is so obviously nutty that it seems to be scarcely worth the time to address it. The second is that it is actually quite difficult to point out precisely what is wrong with it!