[By Alex Gregory]
I'm running with a kind of "philosophical methodology" theme on here so far, so I'll run with that for this post.
"entities should not be multiplied beyond necessity."
"the fewer assumptions an explanation of a phenomenon depends on, the better it is."
"preference for the least complex explanation for an observation"
There are various ways in which this ideally needs qualifying. First, we must balance up the theoretical virtue of simplicity against other theoretical virtues, such as predictive power. Are other virtues lexically prior to simplicity, or is simplicity more weighty than that? Second, we need some idea of what counts as simplicity. Often fewer entities entails more complex processes about how those remaining entities provide an explanation. How do we weigh the various facets of simplicity against one-another? Still, despite these problems, Occam's Razor is a popular tool, both in and out of philosophical discourse.
An incredibly dominant atheist suggestion is that it is up to theists to prove that God exists, in exactly the same way that it would be up to someone to prove that Santa Claus, or Fairies, existed, if they were to hold that belief. That is, the burden of proof is assumed to be on the theist. This seems to be the result of Occam's razor type considerations.
But I think this picture is misleading. The theist does not assert everthing the atheist does and more. They assert a whole picture that looks very different. The atheist (I simplify) is often thought to merely assert that natural facts exist, nothing more. In contrast to this, some take the theist to be asserting this picture, plus a God overseeing it all. But this is false, at least as far as my understanding of religion goes. Theists tend to believe that the natural facts are caused by, maintained by, and/or even constitute, God. In other words, I wonder if the natural facts are not something in addition to God for the theist. Both therefore assert the existence of one entity - for the atheist: the natural facts, and everything associated with them; for the theist: God, and everything associated with him.
If this picture is correct, there is no obvious sense in which Occam's razor supports atheism over theism. There is no burden of proof particuarly on the theist. Atheists must provide reasons to think that God doesn't exist just as much as theists must show that she does.
Of course, I think that there are other, very obvious, considerations which do such provide positive reason to think theism false. The problem of evil is an obvious choice, but also other things such as that most major religious texts contain statements that seem flat out false.
There's two reasons why I think this stuff is interesting. First, given the huge numbers of believers in the world, I find it hard to believe that Occam's razor provides such a knockdown refutation of theism as some people like to believe (maybe I'm relying on something related to Richard's epistemic principle here?). Second, I've often thought that the sceptic elsewhere (epistemology, ethics) is wrong to assert that the burden of proof is on the objectivist. I've recently realised that this is at odds with the view that the burden of proof is on the objectivist in the religious case.