Astrophysicist Sir Fred Hoyle, who was a Darwinist, atheist and anti-theist, reportedly stated that the "probability of life originating on Earth is no greater than the chance that a hurricane, sweeping through a scrapyard, would have the luck to assemble a Boeing 747."
The basic argument against the idea of empirical theism goes back to David Hume, who's argument ccan be summed up in the popular phrase, "Who designed the designer?"
Dawkins writes that Evolution by natural selection is the only workable solution to the question of life's origin on Earth, and since it requires fewer assumptions than the God Hypothesis, Occam's Razor demands that we accept evolution over God.
This argument forms the central argument of The God Delusion and can be read here.
There are a few problems with this.
First is that evolution by natural selection is not a workable solution for the origin of life on Earth. Evolution does adequately explain how that life moved from simplicity to complexity, but it does not explain how it began to exist in the first place. Richard Dawkins admits this.
The fact that evolution does not explain the origin of life on Earth does not mean that we must therefore accept God as the answer. It only means that evolution, by itself, is not sufficient reason to reject God as the answer.
This leads to the second problem. Even if evolution by natural selection is a reality, which I believe that it is, it does not mean that we must reject God as a reality. There is nothing in evolution which disproves God, or even affects His probability of existence. At best, it disproves Young-Earth Creationism, but it actually strengthens Old-Earth Creationism.
Even Charles Darwin said that a man "can be an ardent Theist and an evolutionist."
Third, Dawkins argues that God is the ultimate Boeing 747 because if He created something as complex as the universe, then he must be even more complex. Therefore, the designer needs a designer. If the universe could not have arisen by chance, then neither could God.
However, Dawkins argues that the universe did arise by chance and that there is almost certainly no designer. Therefore, Dawkins argues that complexity does not require design. However, complexity could be designed, it is simply not required.
For example, it very well could be the case that the universe was designed, since it is possible that complexity would come about by design, but it is also possible that the universe's designer was not designed, since design is not required for complexity.
Not only is Dawkins' argument self-refuting, since he does not believe that complexity requires design, but it also completely fails to even address the issue of God's existence for the same reason.