The beauty of Darwin's theory of evolution is that it explains how complex, difficult to understand things could have arisen step by step, from simple, easy to understand beginnings. We start our explanation from almost infinitely simple beginnings: pure hydrogen and a huge amount of energy. Our scientific, Darwinian explanations carry us through a series of well-understood gradual steps to all the spectacular beauty and complexity of life.
The alternative theories, that it was all started by a supernatural creator, is not only superfluous, it is also highly improbable. It falls foul of the very argument that was originally put forward in its favour. This is because any God worthy of the name must have been a being of colossal intelligence, a supermind, an entity of extremely low probability--a very improbable being indeed