I think that Ben has a point in arguing that Occam's Razor is always handy. But the important thing is that we apply it at all steps of the logical process. As Ben notes, once you get past the origin of matter itself, you can fiddle around a bit and find a way that life could have sprung into being. And then, because life is indeed evident as a fact, one surmises that this is how life must have come about.
But this is simply an unacceptable leap of logic. You cannot leap from could to must. That is a leap of faith, and fatal to logic. My argument, as noted in earlier posts and my American Spectator article on Antony Flew, is that the very first premise, which Ben has astutely brought up, is in fact the esential one, and I will now make the further point that anything that depends on that premise is suspect. To wit: until you can show us how to make matter appear out of nothing, you have nothing on which to base Darwinism. You may very well say that you simply have to have that hypothesis, given that the cosmos is here and life is here and so it must all have happened somehow, but that is not an argument for anything at all. It establishes nothing. Hence, for a truly reasonable person the argument over Darwinism must be based on whether the fossil record and other evidence show that evolution by natural selection is the simplest explanation that fits the facts. Unfortunately, it is not, because it does not fit the facts. We have never seen a single instance of interspecies evolution, only intraspecies evolution, which nobody denies. Evolution by natural selection is certainly possible and perhaps even plausible, but the facts to support it have yet to be adduced. Hence, one should feel free to dismiss it and still consider oneself perfectly reasonable and scientific.
But then, it is fair to complain, we seem to be left with no defensible scientific explanation of the origin of life, the origin of species, or the origin of matter and energy. That is correct. My point is that no explanation of these things is fundamentally scientific. Let me state it again: no explanation yet offered of the origin of matter and energy, or of the origin of life, is fundamentally scientific. In this utterly essential regard, theists and atheists are on level ground. We should apply Occam's Razor to all claims, and to all the premises behind those claims.
Whatever can be proven from the facts of the world, we should accept as true. Whatever cannot, should be a matter for free and open debate. Those who would close off such debate should be seen as nothing more than superstitious bullies.