I went to America a few weeks back and met someone who held an opinion I had never seriously considered before - they didn't believe the theory of evolution. To me, this was bizarre, like saying you didn't believe in tables or something. Since then I've started noticing nodes like The Theory Of Evolution Is Not A Valid Theory. This is my small attempt to stand up for sanity.

The five virtues of a valid hypothesis are laid out in 'The Web Of Belief' by W.V. Quine and J.S. Ullian (one of the foremost works of ontology). Those virtues are conservatism, modesty, simplicity, generality and refutability. So how does the theory of evolution hold up?

  • Conservatism
    Defined as: "The less rejection of prior beliefs required, the more plausible the hypothesis - all other things being equal." It seems evolution doesn't do very well here, as it turned most previously held ideas on their heads. But note the rider that Quine and Ullian added: "all other things being equal". Before Darwin, the origin of the species was an area populated by many beliefs but few theories. Evolution does not affect any other proven facts, only theistic beliefs and human vanity.

  • Modesty
    Evolution is entirely self-contained. There is no corollary which we must hold to be true before we can accept evolution as being true. Compare with other theories, which require a belief in a second hypothesis (for instance, the existence of an omnipotent god). Evolution stands or falls on its own.

  • Simplicity
    The cast of Seinfeld are descended from amino acids? Preposterous! (well, except for George) Actually, while the implications of the theory are enormous, the fundamental idea of natural selection is extremely simple. We know that offspring are slightly different from their parents. We also know that organisms that are suited to their environment will live longer than unsuited organisms. Occam would be happy.

  • Generality
    Evolution is not a special case for humans. It applies to all organisms everywhere in the universe. This makes the theory not only valid, but extremely useful. It can even be applied to non-biological entities, such as E2. Other theories about the origin of humanity suffer here, as they treat humanity as a special case and fail to account for the emergence of the billions of other species to have lived on this planet.

  • Refutability
    The theory of evolution does not contain loopholes or unverifiable opinions. It does not, like most other theories which deal with mankind's origins, assume some momentous event of which no records or evidence exists. It can be refuted quite simply - produce a fossil which clearly doesn't fit into any evolutionary tree. If even one appears that can't be explained, then the entire theory is bunk and we have to go looking for a new one.
Of course, none of this actually proves the theory of evolution. But it is, without a doubt a valid theory.
Notes:
1. This is not intended to be a discussion of biology, but logic. As I said, it was inspired by The Theory Of Evolution is not a valid theory, which attempts to use rules of basic logic to disprove the theory. Oh, and by the way, predictiveness is not an essential virtue of a good hypothesis.

2. Religion is mentioned quite a bit here. It's not that I have a problem with faith, it's just that creationism is pretty much the only alternative to evolution. If anyone knows of a decent scientific alternative to evolution, please let me know. I'd love to hear it.



BTW - I, personally, don't like back-and-forth arguing between writeups, so I'm only going to answer questions by /msg. Any errors in this writeup which are brought to my attention will gladly be amended.