Godel, a 20th century, Austrian American mathematician attempted to use the rigour of formal mathematical logic to provide a proof for the existence of God. Whilst somewhat daunting, a more simplified version can be regarded as, “God, by definition, is that for which no greater can be conceived. God exists in the understanding. If God exists in the understanding, we could imagine Him to be greater by existing in reality. Therefore, God must exist.”
This logic was criticised by David Hume amongst others – as it jumps from the premise that because God could be greater in reality than imagined, therefore he must exist in reality – whereas no must is required.
Still it is an interesting example of the relationship between maths and philosophy, and how the underlying logical nature of mathematics can be applied to philosophical questions.