Oops typo, my previus post should have read that evolution claims that the complexity of life is the result of mutation + natural selection.
I myself am not religious. I reject the inclusion of an intelligent designer into the field of biology as his existence cannot possibly be tested or observed. (Even if we witness what appears to be design, we are only witnessing the "product" - we do not see the producer.) I do not, however, reject the possibility that such an intelligent designer exists. He very well could. I don't know, and I'm not willing to have faith. But whether or not he exists is a moot point for science unless he reveals himself. As the New Testament says, though, "Thou shalt not tempt the Lord thy God."
I'm happy that you and I have had a civil and courteous discussion on this issue. All too often, supporters of evolution label creationists as rubes and backwards. From the reverse side, supporters of creationism resort to charges of atheism, propaganda, and secularism with unnecessary frequency.
So, it's good to have a calm discussion.