For hundreds of years, many philosophers have been struggling to try and explain consciousness in the language of science. So far, a good number of philosophers would confess that they have failed. Despite this failure, many philosophers are unwilling to accept a long-standing solution – the existence of souls. Why is this? One of the objections to the "soul view” (a.k.a. substance dualism) cites Ockham’s razor. This principle states that entities should not be multiplied past what is needed to explain something. In other words, given two equally good explanations, the simpler one should be preferred. When this principle is applied to the existence of souls, the simpler explanation is that only one thing exists – physical bodies – rather than physical bodies and souls. (Or, at least, this is how the objection goes).
The problem with this objection is that simpler explanations should only be preferred when they can account for all the evidence equally well. In the case of consciousness, reducing it to physical bodies/brains does not account for all the evidence. There are several reasons for this including the argument from intentionality. Put simply, the argument states that thoughts are about other things; we can have a thought about the sun or about dancing. But physical things are never about other things, they simply exist. Therefore our thoughts cannot be reduced to our physical brains. This argument, in combination with other arguments, means that Ockhams’ razor cannot be used to reject the existence of souls. The Christian philosopher, J.P. Moreland (Ph.D. in philosophy, University of Southern California), makes this point when he writes,
Dualists can agree that one should not postulate dualism [i.e. souls] needlessly, but they insist that dualism [i.e. souls] is, in fact, needed to explain honestly and fairly, important, uneliminable features of human beings. The real debate, then, is not about Ockham’s razor, but about the relative merits of dualism [i.e. souls] versus physicalism [i.e. only physical bodies/brains exist].
James Porter Moreland and William Lane Craig, Philosophical Foundations for a Christian Worldview (Downers Grove, Ill: InterVarsity Press, 2003), 245.