Friday, June 13, 2008

Lycan's four objections to substance dualism

Josh Hickok, on Pretentious Apologetics, responds to four objections to substance dualism by William Lycan. Interestingly enough, Lycan himself seems to have moved away from a strong commitments to the objections to substance dualism, now claiming that they are overrated. However, Keith Parsons gave those arguments against dualism in our Philosophia Christi exchange in 2003, and I responded to those objections as follows: "Some Supernatural Reasons Why My Critics are Wrong", Philosophia Christi vol. 5. no. 1 (2003).

Lycan argues that Cartesian minds do not fit with out otherwise physical and scientific picture of the world and that they are not needed to explain any known phenomenon. But this argument seems to assume that my argument to the contrary is incorrect; if my argument is successful then we need something inherently rational to explain the existence of reason in the world. So simply to assert that we do not need souls to explain any known phenomenon is to beg the question against my argument, since my argument maintains that something nonmechanistic must explain our capacity to reason. And it is not the case that we know nothing about such a soul. We know, as a consequence of the argument, both that it is governed by reason and that reason reason can be a basic explanation for what it does.

Second, Lycan says that since human beings evolved over aeons by purely physical processes of random mutation and natural selection, it is anomalous to suppose that Mother Nature created Cartesian minds in addition to cells and physical organs. Again, this assumes a strong version of evolutionary imperialism that is certainly open to dispute. If my argument is successful, then the human mind could not have arisen through a purely physical process of mutation and natural selection, for, if it had, we would not have been able to discover that we arose through a purely physical process of mutation and natural selection. On the other hand, if theism is true, then it is hardly beyond the powers of Omnipotence to create souls or to give matter the capacity to generate souls.

Third, Lycan says that if minds are nonspatial, how can they interact with physical objects in space? First, I never said that souls were not in space, so I do not see why I have to take this objection seriously (unlike Descartes, who explicitly denied the spatiality of souls). Second, I have never heard anyone argue that since God is not in space, God could not create the world (a causal interaction if there ever was one). So if this is a good argument against dualism, the atheists have been missing out on a good argument for atheism. But it certainly seems logically possible for something that is not in space to interact with something that is in space; the claim that it is impossible is all too often made as a bald assertion, without argumentative support.

The violation of conservation laws does not strike me as a serious problem either, because the laws of nature tell you what happens when nothing outside the system interferes with it. If we are thinking of the soul as outside the physical order, and conservation laws tell us what will happen within the physical order, then it does not violate those laws if something from the outside that order causes something to occur that would not have happened otherwise. The argument works only if physicalism is true, and thus begs the question.

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At 6/16/2008 08:07:00 AM , Blogger Blue Devil Knight said...

Interesting stuff about spatiality.

CoE is violated in quantum mechanics, so that argument is a little outdated. On the other hand, there is no evidence that brains use quantum effects. Indeed, they seem to behave classically for the most part (e.g., even the Nernst Potential that derives voltages based on individual ion species' behavior is classical statistical mechanics.

I think a much more fruitful attack on interactionist dualism would be to try to make a strong case against it for simple organisms like the leech or C. elegans. Then, see if those conceptual resources can scale up to critters with more complicated nervous systems. That would be a very interesting study! Any budding philosophers out there, that's a journal publication. Even dualists might argue that even for the leech there is no good argument against interactionist dualism, turning the argument on its head (though I doubt such an attempt would succeed).

At 6/16/2008 08:06:00 PM , Blogger Doctor Logic said...

We know, as a consequence of the argument, both that it is governed by reason and that reason reason can be a basic explanation for what it does.

How can the basicness of X be an explanation for X?

Surely, a thing's being basic means it is inexplicable.

At 6/17/2008 06:59:00 AM , Blogger Darek Barefoot said...


>>How can the basicness of X be an explanation for X?<<

That assumes that by "what it does" Victor is refering to reasoning. He may be refering to deciding or acting, for example.

>>Surely, a thing's being basic means it is inexplicable.<<

Yes, but "inexplicable" need not mean "has no interesting implications."

At 6/17/2008 12:27:00 PM , Anonymous Anonymous said...

I'm new here (I'm a regular at I read Reppert's book several years ago, and had just recommended it in one of our discussions. Then Doug told me about this blog. I was pleasantly surprised to find out it existed.) Has Victor ever discussed Aristotelian Dualism as an alternative to Substance Dualism?

At 6/17/2008 12:28:00 PM , Anonymous Anonymous said...

Hmmm...actually I go by "Bilbo," not anonymous, but I don't remember my password.

At 6/20/2008 01:52:00 PM , Blogger Rino said...


I actually have a friend doing a PhD on the C. elegans, with the hope of achieving the exact thing you speak of. Even if a complete reduction is possible with the C. elegans, though, this does not mean the same holds true for humans. I guess one wants to start somewhere though.

Could you comment further on how quantum mechanics violates CoE. I've heard this point before, but would be interested in hearing your comments on it.

At 6/22/2008 09:19:00 AM , Blogger Blue Devil Knight said...


That is great that your friend is doing this! As I said, you then have to see if the conceptual resources will scale up. Some of them will, perhaps some won't. One thing that will be discovered, likely, is that we don't need any dualism for C elegans--neurotransmitters cause muscles to contract, and moving backward there is noplace in the causal chain that requires anything but voltages, currents, neurotransmitters, neuronal architecture, that sort of thing. Of course, there is no evidence from biology that anything else is needed for vertebrate systems. It would be good for the dualists to learn some neuroscience and pinpoint exactly where in the brain (either anatomically or functionally) they think such explanatory resources will fail us.

I'm not a physicist, but quantum tunneling (I've been told by a physicist) violates conservation of energy. A particle jumps over an energy barrier very quickly (like a ball rolling up a hill without any outside force). It has to happen very quickly as there is an uncertainty relation between time and energy, and somehow this allows for violation of CoE.

At 9/18/2008 10:46:00 AM , Blogger Invisible Pills said...

Excellent Post, and I do enjoy all of BDK's responses. I stumbled upon this site by accident last night when I ended up reading a post from 2006 in regards to Keith Augustine's challange and found BDK to be very insightful. I know, I sound like a groupie blogger, I am just glad that this is still a relevant topic to discuss since I have always been intrigued by dualism.


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