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.


Timmo said...


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.

I wonder if, from the naturalist point of view, this line line of argumentation can really be upheld. Suppose that both naturalism and dualism are true: there are just two general sorts of things in the Nature, minds and bodies. So, there may be three sorts of laws for science to study: for body-body interactions, mind-body interactions, and mind-mind interactions.

So, a naturalist who was persuaded that dualism in some form is true (say by the appeal to qualia), could deny that the physical processes described by evolutionary biologists could not result in minds as entities over and above the bodies of the organisms that have them. It only seems anomalous that evolutionary biology could result in Cartesian minds because we have hitherto only understood body-body interactions, but the limitations in our present understanding do not bar the possible discovery or objective existence of mind-body laws appropriate for the appearance of Cartesian minds on the stage.

Imagine, much to the surprise of the scientific community, that parapsychologists succeeded in demonstrating the existence of telekinesis, telepathy, and clairvoyance under reproducible, experimental conditions. Moreover, they succeeded in developing theories which accurately described these phenomena. To be sure, dualism would win the day in this case (any of the so-called psi-phenomena would violate basic laws of physics). Question: would the parapsychologists thereby have shown naturalism to be false? Or did they just come across another aspect of nature, the peculiar case of "psi"? (Despite the enormous fraud in this field, there are some serious scientists working in it! Check out Antony Flew's paper "Parapsychology: Science or Pseudoscience?" in Patrick Grimes book Philosophy of Science and the Occult.)

The point of the analogy is not to endorse parapsychology or say that dualism is no different from ESP. The point is just to illustrate that dualism and naturalism are not logically incompatible. Indeed, I do not think that dualism, even if true, really counts against naturalism.

Darek Barefoot said...


Naturalists as a rule want to exclude certain "supernatural" entities such as God, angels, and immaterial souls, as well as violations of laws of physics. If the "paranormal" is admitted in spite of contravening physical law, it becomes harder to close off any possibilities whatsoever. If naturalism just means, "Whatever is, is," then it no longer is of use to most proponents of naturalism.

Timmo said...


Yes, I understand that naturalists typically want to rule out entities like Cartesian minds from their ontology. However, I do not think the a priori insistence upon physicalism is really consistent with other naturalist commitments.

Naturalism comes with a metaphysical thesis (M) and an epistemological thesis (E):

(M) The only things which exist are precisely those entities which are required by (an ideal) natural science to explain the phenomena we (could) observe in the world.

(E) The only way to acquire knowledge about the world is empirical; there are no a priori ways to come to knowledge about the world.

Quine, a paradigm case of a naturalist, is not a physicalist. Quine posits abstract, mathematical objects in addition to the physical bodies in space-time because they are indispensable for natural science. This is consistent with both (M) and (E). If a naturalist can hold that physicalism fails when taken generally and still count as a naturalist, why can't one hold that physicalism also fails for some organisms?

In the hypothetical scenario I offered, physicalism is inadequate to explain phenomenona in Nature that we observe. Moreover, parapsychological theories qualify as robust, scientific theories which are needed to explain the phenomena in the world.

My point is just this: naturalists should only adopt physicalism if the best scientific theories pertaining to human psychology are physicalist. However, there are a number of psychological phenomena, e.g. consciousness, which have yet to be explained in physicalistic terms. Maybe this is possible; maybe it isn't. And naturalism, the conjunction of (M) and (E), is consistent with both possibilities.

Darek Barefoot said...


Your point is consonant with Hempel's dilemma. However, the dilemma is taken to apply to physicalism as well as naturalism. Does what we "could observe" and what we "acguire knowledge of empirically" qualify as "physical" for that very reason? Possibly it does, at least in the minds of some physicalists.

BTW, do you thinks E qualifies as knowledge acquired empirically?

Timmo said...

Hempel's Dilemma is a challenge to any substantive formulation of physicalism. Either the physical objects which physicalists think populate the universe are either (i) the ones described in contemporary physics or (ii) they are objects which some future, complete physics describes. If physical objects are just those things described by contemporary physics, then physicalism is false. Contemporary physics (taken to be, perhaps, the Standard Model) does not purport to be an exhaustive description of the world, and it is clear that it is not. On the other hand, if objects in the world are defined with respect to some future science or physics, then there is no reason to rule out non-physical entities -- who can say what the science of a more advanced, future generation will look like?

I am not sure what to make of Hempel's Dilemma. Are we really that uncertain about what it means to say of some object that it is physical? We have many paradigm examples of physical theories, including medieval theories, Cartesian and Newtonian mechanics, and modern physics. The question is whether there is a common notion of what physical objects are, or if there is some family of characteristics that all draw off of. Maybe there are Kuhnian discontinuities between these approaches to the world, and there is no (partially) shared notion of the physical between them!

In any case, I do not see how Hempel's Dilemma can be construed as an argument against naturalism. To get the dilemma going, we start here: either the entities which naturalists think populate the universe are either (i) the ones described in science or (ii) they are objects which some future, complete science describes. Clearly, naturalists will simply opt for (ii).

What I have in mind is something more like Chomsky's objection to physicalism. Let's call the 'naturalistic project' (with respect to minds) the attempt to understand psychological and behavioral phenomena exhibited by living organisms using scientific methods. The physicalist project is manifestly different from the naturalistic project: philosophical argumentation is not a part of the naturalistic project (though I think this statement probably needs qualifications). We see from (E) and (M) that naturalists should ally themselves with the naturalistic projects in the sciences, rather than the philosophical, metaphysical program of physicalism.

It is this last moral that I am driving at. The scientific attempt to understand psychological phenomena need not be a physicalist one, only one that is empirically adequate, self-consistent, and has whatever other virtues one thinks scientific theories ought to have. It's just an assumption on Lycan's part that the naturalistic project with respect to minds is going to turn up with physicalist explanations (whatever exactly those are supposed to be). This looks like an a priori assumption which is incompatible with (E).

Does (E) qualify as knowledge acquired empirically? Myself, I doubt that (E) is true. Logic, mathematics, conceptual analyzes, and normative ethics all seem to proceed with at least an a priori component.

Self-defeat looms large for naturalists here. I am not a professional philosopher, so my experience is very limited. But, I have never read a paper or a book by a philosopher defending (E) with empirical evidence gathered from psychology. My hunch is that it could be done, though. Philosophers like Goldmann and Kornblith who work in
naturalized epistemology insist that epistemology ought to make use of scientific results pertaining to human reasoning, learning, and beliefs. Quine went further and simply wanted to replace epistemology with the empirical study of how we come to hold the beliefs we do!

So, one might be able to defend (E) on empirical grounds -- why not?

Ilíon said...

Isn't "promissory materialism" the greatest thing since sliced bread?

Darek Barefoot said...


>>But, I have never read a paper or a book by a philosopher defending (E) with empirical evidence gathered from psychology. My hunch is that it could be done, though.<<

Any such attempt would have to subsume the evidence-gathering assumptions of the philosopher/observer. Also, there is a possible equivocation over "empirical knowledge." Is such knowledge strictly limited to that which is "observed"? To what is observed plus whatever presuppositions are required to transmute raw sensory data into evidence? To what is observed plus that for which observation is a necessary but not sufficient condition for being known? Does introspection count as empirical observation? Etc. If "empirical knowledge" casts too wide a net, naturalism becomes vacuous.

Anonymous said...

I go the name of Bilbo, but I haven't figured out that password thingy. 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?

By the way, I posted this over at "2", before I noticed there were different comments over here. How does one know where to carry on a conversation around here?

Anonymous said... way to edit comments. That's supposed to be "I go by the name of Bilbo."

Timmo said...


You rightly point out that an empirical effort to establish (E) is going to face methodological issues. But, antecedent to a serious attempt to work through those issues, I am not willing to dismiss the possibility that such issues might successfully be worked out.

Still, as I mentioned above, I think (E) is implausible. Logic, mathematics, conceptual analyzes, and normative ethics all seem to proceed with at least an a priori component.

Ilíon said...

Bilbo: " way to edit comments."

Try to get in the habit of clicking the "Preview" button, reading what you've written, editing it if necessary, *then* clicking the "Publish" button.

Bilbo said...

"Try to get in the habit of clicking the "Preview" button" -- Ilion.

I'll work on that. Meanwhile, has the subject of Aristotelian Dualism ever been discussed around here?

Ilíon said...

Bilbo: "I'll work on that."

No, no, no! I wasn't trying to say "You need to work on such-and-such." I was trying to give you a tip on how to work with one of the shortcomings in the Blogger software.

Bilbo: "Meanwhile, has the subject of Aristotelian Dualism ever been discussed around here?"

I suspect it has, but I don't know.

Bilbo said...

But I do need to work on it. I'm used to posting where editing is possible.

So how do I get Victor's attention about the Aristotelian Dualism thing?

I'm asking about this, because I recently heard a professor at Calvin College, John Cooper, offer Aristotelian Dualism as an alternative to Substance Dualism, that he thought would work better in describing our experience. Not sure if Cooper has anything on-line about it. I'll have to check.

Victor Reppert said...

I comment briefly on Leftow's Aristotelian dualism in my review of the Corcoran volume in Faith and Philosophy. First, I would ask if Aristotelian dualism isn't a type of substance dualism. Second, we need to know whether AD accepts the conclusion that there are no purely material objects. If so, does that create a conflict with what science knows to be true.

Anonymous said...

lycan's are here the stil live maby its your neabur or jour mother child you dont know the knowing it befor you know it but look out if the are angry the are not happy