Tuesday, February 12, 2008

Beversluis, Kim, and C. S. Lewis on causal closure

Here is an interesting passage in Beversluis chapter on the argument from reason:

JB: Naturalists believe that everything that happens within the total system is caused by something internal to it, so that nothing is independent in a way that enables it to escape this vast interlocking causal web. In short, nature is a self-contained and closed system. By "closed" Lewis means causally closed. So defined, naturalism is a form of determinism--the philosophical theory that everything that happens, happens necessarily as a result of antecedent causes given which nothing could else could have happened. So by naturalism, Lewis means deterministic naturalism. thus, he declares, "no thoroughgoing naturalist believes in freee will (M1, 17). It is important to notice that his argument depends on the assumption that there are ony two alternatives: deterministic naturalism and supernaturalism. If other choices exist, the refutation of the former would not entail the truth of hte latter, as Lewis claims it does.

VR: So in this passage Beversluis commits Lewis to understanding naturalism as deterministic, with the implication that forms of naturalism that deny determinism are not naturalistic. Intereesing Lewis does discuss the denial of determinism through quantum-mechanical indeterminism and says that this would be a rejection of strict natruralism but not an affirmation of supernaturalism, since it would admit a Subnatural realm rather than a supernatural realm. I have discussed this in a couple of posts, but what I had not seen before was the fact that Beversluis seems to think that causal closure entails determinsm.

As defined by contemporary philosophers such as Jaegwon Kim, closure does not entail determinism. Kim writes:

JK: The first of these is the principle that the physical world constitutes a causally closed domain. For our purposes we may state it as follows:The causal closure of the physical domain. If a physical event has a cause at t, then it has a physical cause at t.
There is also an explanatory analogue of this principle (but we will make no explicit use of it here): If a physical event has a causal explanation (in terms of an event occurring at t), it has a physical causal explanation (in terms of a physical event at t).8 According to this principle, physics is causally and explanatorily self-sufficient: there is no need to go outside the physical domain to find a cause, or a causal explanation, of a physical event. It is plain that physical causal closure is entirely consistent with mind-body dualism and does not beg the question against dualism as such; it does not say that physical events and entities are all that there are in this world, or that physical causation is all the causation that there is. As far as physical causal closure goes, there may well be entities and events outside the physical domain, and causal relations might hold between these nonphysical items. There could even be sciences that investigate these nonphysical things and events. Physical causal closure, therefore, does not rule out mind-body dualism--in fact, not even substance dualism; for all it cares, there might be immaterial souls outside the spacetime physical world. If there were such things, the only constraint that the closure principle lays down is that they not causally meddle with physical events--that is, there can be no causal influences injected into the physical domain from outside. Descartes's interactionist dualism, therefore, is precluded by physical causal closure; however, Leibniz's doctrine of preestablished harmony and mind-body parallelism, like Spinoza's double-aspect theory,9 are perfectly consistent with it. Notice that neither the mental nor the biological domain is causally closed; there are mental and biological events whose causes are not themselves mental or biological events. A trauma to the head can cause the loss of consciousness and exposure to intense radiation can cause cells to mutate.

VR: In short, the causal closure principle doesn't imply that there are determining physical causes for every event, only that there are no non-physical causes for any event. The argument from reason, on the other hand, if successful, intends to show that there are non-physical causes for the mental states involved in rational inference. The causal closure principle that Kim presents is sufficient to generate argument from reason. If Lewis had had Kim's definition of causal closure to work with, he would not have saddled the naturalist with determinism, but the argument from reason would not have been effected, since if the AFR works, it requires not merely the denial of physical determinism but also of the causal closure principle as defined by Kim.

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At 2/12/2008 01:55:00 PM , Blogger normajean said...

Vic, you don't seem so impressed with arguments from determinism?

At 2/13/2008 06:36:00 AM , Blogger Darek Barefoot said...


>>The argument from reason, on the other hand, if successful, intends to show that there are non-physical causes for the mental states involved in rational inference.<<

If "mental state" above is a non-physical state, then this says that there are non-physical causes for non-physical states, which is consistent with Kim's version of closure, isn't it?

Somehow the nature and extent of dependency of the mental upon the physical must be brought into play to generate a conflict.

At 2/13/2008 09:24:00 PM , Blogger Victor Reppert said...

But of course, what I think affects what I do, so sooner or later, there goes closure.

At 2/23/2008 10:07:00 AM , Blogger normajean said...

Victor, do you argue in your book that naturalists must be committed to epiphenomenalism?

At 5/04/2008 12:45:00 AM , Blogger rpritchie said...

Per this post and others on the blog, I am very confused by the assumed tenability of a worldview that does not allow for free will or mental causation. That is, I am sure there is a reason for this assumption, but it is not at all apparent to me.

For example, I am willing to accept for the sake of argument all past events despite their apparent complexity under a “a million monkeys typing for a million years type argument;” however, I feel that the general ignorant public—of which I am a member—are still left with an untenable view of naturalism.

I have concocted an example to illustrate. My question is, how with a merely ‘epiphenomenalistic’ mind could individuals be expected to predict the behavior of other organisms with a greater probability of being accurate than picking at random from all possible (or even impossible, perhaps, but, for the sake of argument I can grant possible) events?

From my understanding, they should not be. Yet people make predictions of future activities of others among countless possible activities with great accuracy as a matter of daily routine. Take for example my guess that Kevin Garnett will be in the Fleet Center later today playing basketball. To say that I am more confident in saying this than I would be by merely picking at random among the possible activities he could do at that time would, to people at my level of understanding, seem so obvious as to appear absurd.

Here is my attempt to breakdown this attack on naturalism:

(1) A naturalistic worldview infers no free will
(2) No free will infers no mental causation
(3) No mental causation infers—at best—no ability to predict future events on the level of the behavior of organisms greater than the picking at random from the entirety of possible future events
(4) I have the ability to predict future events at a level much more accurate than a random selection of possibilities would infer.


(5) The probability of naturalism being true is no greater than 1/x where x = the total number of future events.


(6) I can do this repeatedly for events wherein x is a very large number


(7) Naturalism is very unlikely to be true.

I do not for a second believe that naturalists are actually alleging to hold a worldview that is this counterintuitive and unlikely; however, I do not know where I have gone wrong. I would assert that anyone maintaining (1)-(5) and naturalism as a worldview is either a lunatic or an ideologue.

Could you debunk my attempt at logic before I lose any civilized tone in talking with naturalists?


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