Evolution is both a fact and a theory. It is a fact in stating what happens; it is a theory in stating why it happens. A more detailed explanation here: click. While we're at it, on the same site is an amazing page about the evidence for evolution: click. (warning: absolutely mammoth document...but then again, that's the point 
). There's also a ton of other interesting information on that site unrelated to evolution (such as the age of the Earth).
@Dave: "Just as likely" implies that we can assign probabilities to those events, which we can't.
). There's also a ton of other interesting information on that site unrelated to evolution (such as the age of the Earth).@Dave: "Just as likely" implies that we can assign probabilities to those events, which we can't.