Apparently, you believe then that faith is unnecessary for a belief in God. After all, if you could show that God existed via looking at physical evidence, then there's no need for faith. But conversely, if you can't show that God exists by looking at physical evidence, then God has no place in the methodological practice of science. The reason that I personally do believe in God has more to do with faith than with the evidence. Doesn't faith still mean believing without any evidence for that belief. That is not science, but that is where a belief in God comes from. It is not contradictory for someone to believe in God, yet to assume that this belief is not necessary to study physical evidence. You simply are considering what can be learned from considering the evidence without any reference to God. Think of it as kind of a game, ie. let's ignore any belief in God, and see what we can learn ONLY by looking at physical evidence. In a way it's similar to modern mathematics. At one time, for example, in geometry, mathematicians only studied geometry that seemed to have some correspondence with reality, ie. Euclidean geometry. For example, if you draw a line and a point, you can only draw one line parallel to the given line. However, it makes perfect sense to study a geometry where you could draw no lines parallel to a given line. You would just have trouble drawing or visualizing it, but it causes no logical contradiction. You could similarly have a geometry where you could draw an infinite number of straight lines through the point parallel to the given line. The point is that geometry became sort of a self contained exercise; anything outside of the geometry itself was irrelevant. Similarly, supernatural phenomena such as God lie outside of the scope of science and as such are irrelevant to science. BTW, I don't believe that you can look at physical evidence and explain the universe without reference to a Creator. Evolution doesn't attempt to do so. Even big bang theory really doesn't do this; it just pushes the question back a bit. What exactly caused the creation of the universe? Why did the big bang happen the way it did? Why are the laws of nature and the values of the fundamental constants what they are? These questions, I believe have yet to be fully explained by science, and may never be.
Satan believes in God and he has no faith in Him.
Faith is a gift from God alone.