Is evolution a scientific theory?
The answer is no, and here’s why:
In order to be a scientific theory, a proposition must be empirically verifiable and falsifiable. Evolution is neither (this is the same reason that String Theory is not science, by the way). Evolution cannot be experimentally verified, and we have never actually observed species transformation. Moreover, it also cannot possibly be falsified, for any discovery made, any fossil dug up, would simply be incorporated into evolution, even if contrary to prior versions of the theory.
Now, it is true that science can be done within the framework of evolution, in the sense that specific versions of evolution theory can be scientifically falsified, but evolution itself, cannot be falsified, and thus is not science. Note that this is true of creationism as well, it itself is not scientifically verifiable or falsifiable, although specific versions of it are.
So now that we’ve got it clear that evolution and creationism are both philosophy, not science, the question is, which is a better philosophical position?
Well, consider the implications of evolution. According to evolution, my hundred thousandth cousin is a monkey, and my hundred billionth cousin is a bacterium. So, in other words, there’s not really any such thing as species, only wildly different races. And metaphysically, it requires that there are no distinct teleological qualities to which various creatures are directed, expect perhaps simply being alive (note here that this is radically opposed to the set of assumptions governing how biologists deal with practical questions in their field).
So, having shown that evolution is a philosophical idea, I have also shown that it is an idiotic philosophy.