Wednesday, January 02, 2008

Reply to a point in Loftus' review of Beversluis

From John Loftus' Review of Beversluis

The Argument From Reason, as best seen in Lewis’ book, Miracles, “is the philosophical backbone of the whole book,” from which “his case for miracles depends.” (p. 145). Lewis champions the idea that if naturalism is true such a theory “impugns the validity of reason and rational inference,” and as such, naturalists contradict themselves if they use reason to argue their case. If you as a naturalist have ever been troubled by such an argument you need to read Beversluis’ response to it, which is the largest chapter in his book, and something I can’t adequately summarize in a few short sentences. Suffice it to say, he approvingly quotes Keith Parsons who said: “surely Lewis cannot mean that if naturalism is true, then there is no such thing as valid reasoning. If he really thought this, he would have to endorse the hypothetical ‘If naturalism is true, then modus ponens is invalid.’ But since the consequent is necessarily false, then the hypothetical is false if we suppose naturalism is true (which is what the antecedent asserts), and Lewis has no argument.” (p. 174).

In response to Parsons' comment, that's not how the argument from reason goes. If naturalism is true, then no one ever performs a modus ponens inference, and this can be for a number of different reasons.

1) If naturalism is true, then there are no propositional attitudes. Propositional attitudes are necessary for modus ponens inferences, so no one would actually ever perform a modus ponens inference if naturalism is true.

2) If naturalism is true, then there is no mental causation. One mental event cannot cause the occurrence of another mental event in virtue of its content, if naturalism is true.

3) If naturalism is true, then logical laws have no psychological relevance. Only physical laws can be relevant to physical events if naturalism is true; logical laws will be followed only if the physical order to disposes the brain to follow them. There could be arguments in accordance with reason but never from reason, to use Kantian terminology. I'm not saying that if naturalism is true there would be no logical laws, but rather those laws would not and could not have anything to do with what anyone things.

In other words, the argument says that if naturalism is true, then no one reasons validly. Modus ponens would be eternally a valid form of inference, but that fact would be completely irrelevant to any actual reasoning processes, and would be inoperative.

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At 1/02/2008 09:32:00 PM , Blogger Edward T. Babinski said...

No one is arguing that science has explained how energy and matter leads to conscious awareness.

But nature does allow us to study the brain and so we can agree that the highly complex organ known as "the brain" has far more to do with consciousness than other parts of the human body. And nature also provides examples of different brains in different bodies/organisms, brains of different sizes and types, from those in amphioxus, a very tiny vertebrate and possibly the closest living relative to all subsequent vertebrates, to the brains of chimpanzees which contain many of the same structures and much of the same DNA as human brains. Also, the fossil evidence provides us with skulls and brain case shapes of species that lived prior to human beings, species with larger brains than any gorilla or chimp living today. We can also study the behaviors of chimpanzees (though sadly we cannot study the behaviors of the early hominids which were most ape-like, nor the late upright apes which were most human-like). But nature has still provided us with lots to study.

In fact if you could substitute single DNA base pairs in the genome of a chimp you could eventually produce a human genome, and a human with a human-like mind (a brain to which you would also then have to add an education and language in order to obtain human thinking patterns and philosophical understanding, for without a human education and language and input from others sharing such cultural evolutionary things that our species acquired with difficulty and over eons, we'd still be grunting instead of speaking).

So a continuing study of nature in my opinion trumps your attempt to short circuit such studies and exclaim that brains and reasoning necessarily involve two things so radically different from one another that one of them has to be "supernatural." You don't know that.

Equally important, haven't you considered that the definition of "physicalism" that you employ in your own head whenever you discuss what is "physical" is itself a mere metaphor? It's not a "solid" definition.

If the brain (and the complex web of energy and memories and inter-relationships it contains) is anything, it is so complex that it is beyond our ability to grasp it's workings simply and easily, because if we could, then we would be so simple we couldn't come up with such questions in the first place. That's about all that philosophy qua philosophy can say about the matter.

And speaking of matter, it's arrangement is crucial. Mere sand and minerals on a beach mixed with electrical energy, if arranged into a computer with its silicon chips (made from minerals also found in sand) can be made into something that is quite different from mere sand. And add in some sensing devices like a camera lens and a computer chip for mental imagery recognition, and perhaps moving wheels on such a computer and it could react to objects in its environment, tell rain from non-rain, and even get out of the rain, acting quite logically. If such can be done with simple silicon chips and matter in nature, then what might not be possible via billions of years of evolution of living reproducing organisms? Might not human brains and consciousness be natural then?

*(This is of course a separate question to the one of whether or not a Designer set the entire evolving cosmos up and running "in the beginning.")

Vic, really, get the metaphor of "physicalism" as billiard balls out of your head already. It's an insufficient metaphor for all the things in the natural world that exist and interact each bringing to light new things at different levels--from atoms to molecules to electro-chemical reactions and ever upward toward whole organs like brains and the differing consciousnesses of various types in organisms with simpler brains to more complex ones over time.

Personally, I'd LOVE to be a dualist, and be able to provide proof like you try to do that human consciousness was separate from the brain and also not subject to the natural world's decay and death I see all around me in all things that live. But philosophical "proofs" strike me as some of the least satisfying when it comes to such questions.

Return to what I wrote concerning "all that philosophy qua philosophy can say about the matter."

At 1/04/2008 12:17:00 PM , Blogger Victor Reppert said...

Billiard balls? Who mentioned billiard balls? Not me!

When we add up all the physical states, we still have information logically compatible with the existence or nonexistence of determinate mental states. But if we literally add, nultiply, subtract, and divide, then it is determinate what our thoughts are about. So mental and physical states are distinct. This is so long as we accept the four bans on what can be attributed to a physical state. The four bans are a ban on subjectivity, a ban on normativity, a ban on intentionality or aboutness, and a ban on purpose. Try building those into physics and people are going to look at you as if you just joined theID movement.


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