"Believe" implies some sort of religious connotation. It aint. Actually, I've never really understood why there are so many of the Abrahamic religions that think that this some how contradicts one's belief in a God. I guess that just illustrates that their dogma is more important than their spirituality, which is a shame.
I don't believe in it, I know it. All the evidence in genetics, biology, geology, and even some of the non related parts of science. It stood up to thousands of peer reviewed papers and even more false claims.