Evolution is not "just a theory"

Evolution is considered as much a fact as the theory of gravity. Do not confuse the common language definition of theory with the scientific one. In common language, the use of the word “theory” is synonymous with “hypothesis”.  When science declares something to be a theory, it is considered an independently confirmed fact.  Despite this, all science is open for critique with evidence.  If contrary evidence arises, then the theory must be revised or dropped.  The fact that life evolved on this planet is not in question in the scientific community.

"But this can't just be some cosmic accident - it's too complex and perfect"

I will concede that the complexity of the universe is a somewhat compelling reason to believe in some sort of intelligence. I believe that we are slowly discovering our universe. I don’t think that our current lack of understanding is any sort of proof of our ancient myticisms.  However, the question of things being too improbable to happen by chance is a fair point.

If you listen to/read some of Richard Dawkins with regard to evolution, you will find that evolution isn’t random chance. The only parts that are random are the genetic mutations themselves. These mutations are mostly failures, but occasionally they are for the better. These successful mutations survive to the next generation. This process has repeated for millions and millions of years, leading us to where we are now.

In his latest book (which I have not read, but have heard podcasts about it), Dawkins paints a compelling picture with a discussion of leopards and gazelles. If you look at leopards, they look like the perfect gazelle killing machine in every way. If you look at gazelles, they look like the perfect leopard avoidance machine in every way.  It appears that leopards and gazelles are magnificently designed.

This perfection is not by mistake or chance though. Thousands of years of natural selection has bred them to be exactly where they are now. If you can’t hunt properly, you die and provide no offspring. If you can’t avoid being hunted, you die and provide no offspring.  The fact that evolution within a species occurs this way is undeniable and not random.

"Ok, but how does a new species form?"

Once some sort of geographic separation occurs, species may evolve to the extent that they can no longer interbreed with their long lost relatives.  This is the scientific distinction of a species.  This evolution, over a large amount of time, can create massive differences in species with a common ancestor.

"But this still has no explanation of how it started and who started it"

Many atheists fall back to the Big Bang as the how and who.  I'm not so sure.  I accept the Big Bang, but I'm very much in the "I don't know" camp with regard to the beginning of life and whether some intelligence was involved.  My gut tells me no, but this is really just a guess.  What I'm more confident about is that it isn't supernatural in a deity sort of way, based on my life's observations and "faith" in what scientists know to this point.  I am not 100% sure, but that's because it's impossible to know at this point.