Wednesday, March 25, 2009

C.S. Lewis and contemporary philosophy

But we cannot possibly conceive of a reason as being consciously directed from outside in regard to its judgments; for in that case the subject would attribute the determination of his power of judgment, not to his reason, but to an impulsion. Reason must look upon itself as the author of its own principles independently of alien influences (Kant, gesammelte Shriften, IV, 448).

Suppose that some agent, say Jones, at time t1 has a belief M1, and the content of M1 is the proposition that ‘either P or Q, and not-Q’. Now suppose that Jones at t2 has a belief M2 and the content of M2 is the proposition that ‘P’. If we want an explanation for Jones’ conclusion that P, we might ask, “Why did Jones think that P?” One explanation could be that Jones deduced the proposition P given his prior premises and the recognition of the logical entailment from the premises to conclusion. However, if physicalism is true, an entirely different explanation can be given. At t2, Jones’ belief that M2 is supervenient on a neurophysiological state N2 (and M1 supervenes on N1 at t1). According to physicalism, N2 is sufficient for M2; that is, no other cause or explanation is required to account for a full explanation of M2; M1 is neither necessary as a cause nor as an explanation. Thus, we have two different explanations, and the physicalist causal explanation rules out explanation by reasons. The content of M1 need not play any explanatory role since the story at the neurophysiological level will be enough to explain why M2 occurred.

Donald Davidson’s anti-reductionist view (with regards to types) does not, according to Jaegwon Kim, solve the problem of mental causation, and thereby does not resolve the incompatibility of rational and mechanistic explanations. Kim states his criticism in the following way:

"What role does mentality play, on Davidson’s anomalous monism, in shaping this [causal] structure? The answer: None whatever. For anamolous monism entails this: the very same network of causal relations would obtain in Davidson’s world if you were to redistribute mental properties over its events any way you like; you would not disturb a single causal relation if you randomly arbitrarily reassigned mental properties to events, or even removed mentality from the world. The fact is that under Davidson’s anomalous monism, mentality does not work . . . What does no causal work does no explanatory work either." (Kim "The Myth of Nonreductive Materialism" Proceedings of APA 63, 1989, 34-5) [italics mine]

Davidson’s account leaves mental states causally impotent since the events that enter into causal relations do so only in virtue of their physical properties. The mental aspect, including its content, plays no causal role. The agent will not hold his belief because of reasons but because of the neurophysiological events that are sufficient for causing another neurophysiological event. Though the neurophysiological event is also, at the same time, a mental event for Davidson, the mental content has no causal relevance. Thus, we are left with a brand of epiphenomenalism that leaves mentality causally irrelevant; so no reasons-explanation.

Another resolution to the incompatibility of mechanistic and rational explanations is to claim that the two are distinct kinds of explanations that “say different things” about the event that they are explaining; in Wittgensteinian terms, they employ different “language games”. Elizabeth Anscombe, a student of Wittgenstein, responded against the charge of explanation incompatibility and argued that reasons-explanations are not causal explanations at all; that is, they do not figure into the causal sequence and so are not in conflict with a causal explanation by physical processes. Her argument was a response to a chapter in a book by C.S. Lewis, where he attempted to demonstrate naturalism/physicalism as a self-refuting thesis. Given the insightful objections by Anscombe, Lewis’ original arguments were deemed defective.

In response to her criticisms, Lewis revised the chapter for a later edition; and though his revised argument has been largely ignored, I believe that the distinctions made are worrisome for any compatibility thesis between physical and rational explanations given the commitments of a physicalist. Essentially, the argument is that reasons-explanation must be causally relevant for the production of the belief, otherwise there is no need to posit such an explanation. If the reasons are not responsible for bringing about the belief, then no belief will be held based on any rational ground. Thus, we must turn back toward finding a causal role for reasons-explanation.

Lewis’ strategy hinges upon a distinction between two different kinds of relations: a connection between cause and effect, and a connection between ground and consequent. The former relation is what holds between physical processes in nature, whereas the ground/consequent relation is a logical relation that holds between propositions. It seems somewhat correct to construe the ground/consequent relation as a reasons-explanation and the cause/effect relation as a mechanistic explanation of physical processes. Instead of merely stipulating their incompatibility, Lewis suggests that unless the ground/consequent relation is causally relevant, an incompatibility will arise since the rational explanation is not necessary for the production of an event:

"Unless our conclusion is the logical consequent from a ground, it will be worthless and could only be true by a fluke. Unless it is the effect of a cause, it cannot occur at all. It looks, therefore, as if, for a train of thought to have any value, these two systems of connection must apply to the same series of mental acts . . . Even if grounds do exist, what exactly have they got to do with the actual occurrence of belief as a psychological event? If it is an event it must be caused. It must in fact be one link in a causal chain going back to the beginning and forward to the end of time. How could such a trifle as lack of logical grounds prevent the belief’s occurrence and how could the existence of grounds promote it." (Lewis, Miracles, 16)

On closer inspection, Lewis’ criticism is fairly similar to the criticism Kim makes in his argument against Davidson’s anomalous monism. Even if reasons-explanations do exist, that is even if reasons-explanation are not reducible to causal explanations, the event can be fully explained in virtue of its causal explanations of physical processes. Rational inference, much like mental-types, turn out to have no causal work. Thus, Anscombe’s resolution falls prey to a similar kind of epiphenomenalism as well. And what has no causal role has no explanatory role as well. So reasons-explanations are not necessary for a full explanation of why an event took place.

What strikes me as interesting is that C.S. Lewis had similar worries regarding the problem of mental causation as Kim does for anomalous monism. And Lewis, I suspect, would probably argue that such worries are also a problem for Kim's reductionist account (cf. Hasker, Reppert). A literary figure doing serious philosophy... awesome... (not too uncommon; see Chaucer wrestling with the problem of "necessity" with respect to God's foreknowledge and human freedom).

Saturday, March 21, 2009

Proud of my Big Bro

My Bro:

"Chief Resident Isaac Yang performs a pupillary and glasgow coma exam on a traumatic brain injury patient at the San Francisco General Hospital as Geoff Manley, chief and professor of neurosurgery, watches over the entire team in the background."

That's my older brother, Isaac...  this picture is on the homepage of

He's a neurosurgeon at UCSF, finishing up next year.  I'm proud to know that he's trying to be a good man.

It's great to see someone excel at something they love doing; especially when such a task can help others.  I'm proud of ya, bro!