This is the second in a series of posts answering the most common objections to substance dualism (see the intro here, and the first response here). I will argue that an appeal to Ockham’s razor does not, at present, carry any weight against substance dualism, and the principle is only relevant as a hypothetical qualifier to the debate.
I should stress again, this series is not making a positive case for substance dualism. Rather, I am trying to expose the standard arguments against substance dualism, which are routinely trotted out as if they were prize stallions, rippling with rhetorical muscle and incapable of being bested in a race, for the tired, creaky old nags that they are. These objections, touted as undefeated champions, can’t even drag their sorry carcasses off the starting line. It’s high time they were sent to the glue factory—er, excuse me, put out to pasture.
Substance dualism posits (at least) two fundamental substances, or two ontological categories, in order to explain the salient features of the world. Materialism posits one. One is fewer than two. (Yes, I did just write that sentence.) So, in that sense, materialism is ontologically “simpler” than dualism, because it posits fewer ontological categories.
Ockham’s razor is the widely held principle that one ought not to multiply ontological categories beyond necessity. In other words, when doing metaphysics, keep it simple stupid. If you can explain the flickering lights in your basement using only physical stuff (electric currents and copper wire) and physical laws (Ohm’s law comes to mind), there’s no need to drag in ghosts and ghoulies and poltergeists. Likewise, if we can adequately explain the mental features of the human mind using only one ontological category (e.g., physical substances), then we have no warrant for appealing to additional categories (e.g., body and soul; res extensa and res cogitans, etc.). Given an adequate explanation of the mind in physical terms, it becomes unnecessary to “multiply ontological categories,” and the non-physical is rightly excised.
But—and this is the all important question—can materialism, in fact, adequately explain the mind? If materialism cannot, even in principle, explain the mind, then an appeal to another ontological category would be warranted, provided it allows for an adequate explanation. And this, of course, is precisely what dualists claim. They claim that materialism cannot even in principle explain consciousness, intentionality, rationality, self-identity over time, unified consciousness at a time, free will, etc., whereas dualism, they claim, can. In other words, a more ontologically complex explanation is appropriate if a more ontologically complex explanation is necessary.
The issue, then, is not whether dualism is more complex. As I said before, one is fewer than two. That’s obvious. Instead, the issue is whether materialism is capable, at least in principle, of an adequate explanation of the mind. Materialists have to first show that they can, at least in principle, offer adequate explanations of the mind before any appeal to Ockham’s razor is relevant.
Too many materialists miss the conditional nature of Ockham’s razor. I have heard dualism rejected on the mere basis that it is “more complex than materialism, and therefore, less preferable.” Instead of Ockham being a discriminating surgeon wielding a scalpel, he becomes an axe-wielding psychopath, chopping at anything in his path. The principle becomes: “Do not multiply ontological categories.” Full stop. The phrase “beyond necessity” is simply ignored.
Now, I fully expect any materialist reading this to demur that materialism can, in principle, explain the mind. Perhaps it can. But an intellectually honest materialist must concede that such explanations have not been forthcoming. Until then, Ockham’s razor is irrelevant as an objection to substance dualism.
Please let me know what you think in the comments.