Saint Anselm, in the Monologion, postulated that there is some one thing that exists which all things exist and that one thing exists through itself so therefore is greater than all other things. The significance of this statement is that Anselm side-stepped the problem of faith in a fairly convincing way. He would later define his position even more sharply in Proslogion.
Religion is philosophy. For a religion to not be a philosophy, it must prove that its deity truly exists. None can do that and they rely upon "faith". The position of faith has been argued since before Anselm's time to the present. Kant worked around the issue with his Categorical Imperative, which loosely outlined, is the work towards the greatest good. Kierkegaard addressed faith as the only way a person can achieve the true self.
But Kierkegaard realized that Christian religion, and I would argue religion in general, harms itself with dogma, because its dogma denies reason because of its paradoxes. To counter this Kierkegaard made his argument of faith through the absurd (suspension of reason to believe in something higher than reason).
Interestingly, Pope John Paul II made this statement: Science can purify religion from error and superstition; religion can purify science from idolatry and false absolutes. Each can draw the other into a wider world, a world in which both can flourish (John Paul II, "Letter to Reverend George V. Coyne, S.J.", Origins, 378.).
It is a tantalizing statement. Science and religious philosophy have virtually always been at odds, basically because science does not require faith; science deals ultimately with absolutes (water exists). If science and religion work more closely, will science remove faith, as faith is superstition? Did John Paul introduce something more dangerous than the faith problem by introducing the possibility that science is religion?
Think about that last statement. Science deals with absolutes. It does not require Kierkegaard's absurd, embraces (to a point) Kant's Categorical Imperative, and also fulfills Anselm's test. For religion to be something other than philosophy, it must prove its deity exists absolutely and therefore remove the need for faith. Following this line, science is the only true religion. I tend to believe that John Paul saw this issue coming to a head in the near future and attempted to stave it off by joining religious belief with science again, as it was before Copernicus.