I came across an interesting article in the Scientific American magazine (April 2007) which provides a Bayesian explanation to Gods existence/non-existence. I found another article with a better explanation, which I recommend you read.

Excerpt [via]:

Hundreds of years ago before the most basic physical laws were discovered, the ordered workings of the universe could be seen as implying an intelligent hand. A godless universe was necessarily disordered and p(U|notG,I) would be nearly zero for the observed universe. The existence of a god would then be the better choice. Morning glories needed a divine nudge to open after every sunrise. The planets needed to be pushed across the sky by angels. Eventually, science could explain these things without resorting to a god and the godless explanation becomes the better choice.

  • Samuel Skinner

    First people to try to do that were the Epicurians… let me see…

    Got it! Lucretius “On the Nature of the Universe”. Given the limited scientific knowledge he had to give explanations for a large number of odd phenomena (why do people live in societies, where does lighting come from, how does the wind work, etc). Obviously, many of the explanations are off, with the one concerning life being the worst. They never heard of natural selection so they settled with random chance.

  • Anand Kishore

    Epicurus also put forth the Epicurean paradox or Problem of evil [http://en.wikipedia.org/wiki/Problem_of_evil] in the following excerpt:

    “If God is willing to prevent evil, but is not able to
    Then He is not omnipotent.

    If He is able, but not willing
    Then He is malevolent.

    If He is both able and willing
    Then whence cometh evil?

    If He is neither able nor willing
    Then why call Him God?”

    There is a logical inconsistency proved in the above excerpt. Details can be found here: http://www.iep.utm.edu/e/evil-log.htm