"Faith is believing in that which I know ain't so." - Mark Twain
"Faith: not wanting to know what is true." - Friedrich Nietzsche
Philosophy combined with rationality makes for a good argument against there being any such thing as a non-corporeal entity known as God. Jungian psychology showed us that all of these gods, devils, angels, and demons were simply archetypal images embedded deep within our unconsciousness and can be brought to the conscious surface by way of Symbology.
Richard Dawkins' book "The God Delusion" remains one of the finest and rational deconstruction of the God myth.
Dr. Michael Aquino of the Temple of Set puts forth the concept (and I agree) that this idea of a God is man's way of trying to explain what is called the Objective Universe (everything known which abides by the Laws of physics), what could be construed as Natural.
Early religions such as Egyptian, Sumerian, Indus Valley (Hindu), saw a gaggle of gods and goddesses as aspects/manifestations of our Self, personifications of our Inner Being, not one omniscient/omnipotent overseer of Man. This even seems more rational and fits better with philosophical, psychological understandings of what a God might be.
No one can prove one way or the other the existence of a God, seems as if God itself cannot even prove its own existence (pretty lame for an omniscient/omnipotent being), but rationale and chances are, there is no such thing as believed to be this Abrahamic god.