Feser on Popper contra computationalism

Following links from Ed Feser's final instalment in his series on Nagel and his Critics I came upon this piece.  It's Ed's presentation of an argument due partly to Karl Popper and partly to John Searle.

1. Materialism holds that thinking consists of nothing more than the transition from one material process in the brain to another in accordance with causal laws (whether these transitions are conceived of in terms of the processing of symbols according to the rules of an algorithm à la computationalism, or on some other model).

2. Material processes have their causal efficacy, including their ability to generate other material processes, only by virtue of their physical properties (i.e. those described by physical science), and not by virtue of any meaning or semantic content that might be associated with them. (For example, punching the symbols “1,” “+,” “1,” and “=” into a calculator will generate the further symbol “2” whether or not we associate the standard arithmetical meanings with these symbols or instead assign to them some eccentric meanings, because the electronic properties of the calculator alone are what determine what symbols get displayed. Similarly, neural processes that are in fact associated with the thought that all men are mortal and the thought that Socrates is a man would still generate the neural process that is in fact associated with the thought that Socrates is mortal even if these neural processes had all been associated with some other meanings instead, because the neurophysiological properties of the processes alone are what determine which further processes get generated.)

3. But one thought can serve as a rational justification of another thought only by virtue of the meaning or semantic content of the thoughts. (For example, it is only because we associate the symbols “1,” “+,” “1,” “=,” and “2” with the standard meanings that “1 + 1 = 2” expresses an arithmetical truth. Similarly, it is only because “All men are mortal,” “Socrates is a man,” and “Socrates is mortal” have the meanings they do that the first two sentences logically entail the third, and only when the neural processes in question are associated with the corresponding thoughts that the first two provide a rational justification for believing the third.)

4. So if materialism is true, then there is nothing about our thought processes that can make one thought a rational justification of another; for their physical and causal relations alone, and not their semantic and logical relations, determine which thought follows which.

5. So if materialism is true, none of our thoughts ever is rationally justified.

6. But this includes the thoughts of materialists themselves.

7. So if materialism is true, then it cannot be rationally justified; the theory undermines itself.
Ed goes on to expand considerably on this and ends with the conclusion,
Hayek argued in The Counter-Revolution of Science, an important critique of scientism, that “the ground for a thorough irrationalism” lay implicit in any view of human beings aimed at “uncovering hidden causes which, unknown to the thinker, have determined his conclusions.” (p. 159). His target was the relativist idea that a person’s race or class situation determines what he thinks. Popper’s claim is that the materialist view that our thoughts are determined by the hidden causal processes uncovered by physical science is no less implicitly irrationalist.

A naturalist's response to Ed's final remark is likely to be that it's precisely the regularities in the physical world revealed by science that guarantee the regularities of logical thought, so the preceding argument has things awry.  How so?

Perhaps the first thing to say is that, contrary to Ed's assertion in the underlined sentence of para (3), the meanings of the categorematic terms in Ed's example syllogism contribute nothing to the validity of the inference.   All we need to know is that Socrates is a singular term and man and mortal are general terms, and in this example this is a purely lexical matter---the upper case 's' in Socrates tells this is a singular term and the lower case  initial letters in man and mortal tell us that these are general terms.  Ed has in fact given us an instance of an inference schema which we can summarise as
P* → Q*, Pa ⊢ Qa,
where P and Q are placeholders for arbitrary general terms and a is a placeholder for an arbitrary singular term.  We can read the schema as follows:
If, for some general terms P and Q, we have the formula P* → Q*,  and if, for some singular term a we have the formula Pa, then we can infer the formula Qa.  
We can model this by a mechanical pattern matching operation on symbol strings or by other physical realisations.  The schema can be seen as the meaning of the syncategorematic term all in the context all Ps are Qs.  So we have found a meaning for all in terms of physical processes.  Perhaps this can be expressed better by saying that we have a morphism between, on the one hand, logico-semantic relations involving the word all and other linguistic terms and on the other hand, causal relations over physically realisable processes.  The physical relations model the logico-semantic relations and vice versa.  They are duals of one another.  But, of course, the salient physical relations here are by no means all the physical relations in our system.  So our morphism is between logico-semantic relations and our physical system seen at some suitable level of abstraction.  At this level of abstraction the two descriptions are equivalent.   This, to my mind, dissolves the either/or distinction Ed claims in his (4), and derails the argument.

How else are the manifest and scientific images  to be put in register?

8 comments:

  1. I posted this over at ing's blog, but I'm not sure that you saw it.

    Consider a biological genus, such as Homo or Pan. They both start with uppercase letters and yet they refer to many different organisms, so they are general terms. Wouldn't something like “American” also be a general term? And you have not eliminated intentionality here. Uppercase symbols point at/tell us “singular term.” And lowercase symbols point at/tell us “general.” Additionally, it is not in the physical properties of the symbol “S” to point at “singular term.” That “property” must be applied to it. Just because capital letters are large sized symbols, does not mean it follows that capital letters denote a singular term. You have to insert an intentional premise for that to work.

    In regards to your diagram, what is the morphism between the enzyme and P*→D*? There has to be some objective physical fact(s) that we can observe in the protein and P*→D* to justify/prove the morphism. Otherwise, you run into premise 2.

    In addition, are you rationally justified in accepting a conclusion that resulted from an argument that was valid, but committed the fallacy of equivocation? Also, take this for example:

    1) All guys are purple.
    2) Bobby was a guy.
    3) Therefore Bobby was purple.

    The conclusion follows from the premises. If the laws of physics indeed "guarantee the regularities of logical thought" won't they guarantee this conclusion? Is the conclusion rationally acceptable?

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  2. Hello ozero91, and thanks for the comment.

    I was afraid my glib use of the initial upper case/lower case convention for distinguishing proper and common names would get me into hot water. You suspect some intentionality is hidden away here. But I think not.

    Twas brillig, and the slithy toves
    Did gyre and gimble in the wabe:
    All mimsy were the borogoves,
    And the mome raths outgrabe. (Jabberwocky)

    The grammatical role of the nonsense words is readily apparent. We don't need to know what they mean to decide whether they are adjectives, nouns, verbs, etc. Likewise, I think, the singular/general distinction. But in the end I could just say that the names we deal with are finite in number and the singular/general attribute is merely remembered, ie, encoded physically, perhaps by the attachment of some distinctive molecule, to pursue my chemical analogy, that enables a general and a singular state to bond together, but not a pair of singulars or a pair of generals.

    The morphism I'm trying to capture carries the proposition All philosophers are dangerous on to the physical brain state P*→D*. The latter entity plays a transformative role within the economy of brain state entities which depends purely on physical principles, ie, requires no intentionality. I try to convey this by offering a chemical analogy: enzymes are physical transformative biochemical molecules.

    Regarding equivocation, I would have to say that my morphism relies on an unambiguous map from inscriptions to brain states, just as we assume an unambiguous map from inscriptions to the corresponding propositions. I guess this means I am assuming an ideal language with no equivocal terms. To the extent that this is unrealistic the theory needs extending to show how equivocation might be detected and corrected on physical principles. But for the purposes of showing that inference is possible without intentionality I think an unequivocal toy language is acceptable.

    Your Bobby syllogism looks fine to me, apart perhaps from the tense issue. Is that your point?

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  3. I don’t have much time at the moment, but I can say this for now:

    “The grammatical role of the nonsense words is readily apparent. We don't need to know what they mean to decide whether they are adjectives, nouns, verbs, etc. Likewise, I think, the singular/general distinction.”

    “General” and “singular” are still intentional. The way I see it, the moment you declare a term or a molecule is “general” you are still applying intentionality to it. You are claiming that the physical structure indeed points to and describes some group of things, even if you do not know if what that group is composed of. If the structure in question indeed had no intentional properties involved, then it would not point to anything at all, not even a group of things.

    Also, consider this:

    1) We have the physical shape “And the mome raths outgrabe” (I say shape rather than symbol because symbols are intentional)
    2) We know the location of “outgrabe” relative to the whole shape (Properties like shape, location, and the wavelengths of light some matter absorbs/reflects are not intentional, so I think the first two premises are indeed non-intentional)
    3) ???
    4) Therefore “outgrabe” is a verb. (Isn’t “verb” also intentional though? A verb is a symbol which refers to an action or event. We might not know what the action or event specifically is, but we know that there is something that the shape refers to)

    Even in principle, what other non-intentional premises could get you to 4? You would have to bring in syntax, which is intentional and not inherent in the physical properties of the shape. Additionally, we can’t presuppose that “And the” has meaning.

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  4. EDIT:

    "even if you do not know if what that" was intended to be "even if you do not know what that"

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  5. Hello ozero91,

    You say that I am claiming that some physical structure indeed points to and describes some group of things, even if I do not know what that group is composed of. Actually, I don't think I am making such a claim---it's just the kind of thing I'm trying to avoid. I don't claim that any of my structures possesses intentionality. I'm not trying to work up a causal theory of intentionality. Rather, I'm trying to show that a bunch of physical states/processes can behave in a way that mirrors logical inference, which I take to be what Ed is denying.

    However, I think you are right if you are saying that I have helped myself to the singular/general distinction. I really need to show how words can be sorted into two classes, the singular and the general, by a purely physical process, not helping myself to any intentional concepts.

    I'd have to say something like this. If we pare simple indicative sentences down to two words they take the form SG, a singular term followed by a general term: Socrates dangerous for example. Sentences of the form SS, GG, or GS never occur. So the classification can be made on the basis of word order. The singular terms are those that occur first and the general terms are those that occur second.

    It occurs to me that this theory is refutable: find a learnable language that is indifferent to word order and I'm done for.

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  6. Thanks for the reply.

    “Rather, I'm trying to show that a bunch of physical states/processes can behave in a way that mirrors logical inference, which I take to be what Ed is denying.”

    I still am trying to grasp the ins and outs of the argument, but I think that Feser is saying that you certainly can have a machine that mirrors logical inference, but only if you apply syntax and semantics to it. Objectively the device is neither rational nor irrational; it is nonrational, it doesn’t involve premises, fallacies, conclusions, etc, but rather it only involves the behavior of matter described by physical laws.

    “You say that I am claiming that some physical structure indeed points to and describes some group of things, even if I do not know what that group is composed of. Actually, I don't think I am making such a claim---it's just the kind of thing I'm trying to avoid. I don't claim that any of my structures possesses intentionality. I'm not trying to work up a causal theory of intentionality.”

    I figured, but I’m trying to explain that you are presupposing it anyway, which affirms Feser’s argument. If your structures are indeed non-intentional, then why are you making use of intentional terms like “general” and “singular” rather than non-intentional terms like mass, force, wavelength, etc?

    “I’d have to say something like this. If we pare simple indicative sentences down to two words they take the form SG, a singular term followed by a general term: Socrates dangerous for example. Sentences of the form SS, GG, or GS never occur. So the classification can be made on the basis of word order. The singular terms are those that occur first and the general terms are those that occur second.”

    Wait a second, if SG is supposed to be a physical structure, then how is it possible to decide which is “first” and which is “second?” Take a hydroxide molecule for example.

    http://en.wikipedia.org/wiki/Hydroxide

    How do you decide whether the hydrogen or the oxygen is “first?”

    “The singular terms are those that occur first and the general terms are those that occur second.” "Sentences of the form SS, GG, or GS never occur."

    What physical fact(s) justify these otherwise arbitrary rules?

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  7. Hello ozero91, and thank you for engaging with me on this.

    Yes, I think you have Ed aright. My project is to try to describe an inferential machine in a way that isn't vulnerable to accusations of building in 'derived intentionality' from the beginning. Hence the worry about singular/general. Logic is all about the interplay of subject and predicate, ie, singular and general terms, so my physical system must have elements that play these roles. But in describing the physical relations between these elements I only use physics language, I hope.

    Just to clarify, I use SG not to denote a physical structure, but to describe the general form of simple indicative sentences. That is, a singular term like Socrates followed by a general term like dangerous. We see that there are two classes of term and a sentence is a complex consisting of two terms, one from each class. To model this physically I just need two well-defined classes of physical entities, distinguished by a single physical property say, that form heterogeneous compounds but not homogeneous ones. The chemical analogy has molecules of two types A and B, say. The As bond with the Bs but not among themselves. Likewise the Bs. There is no requirement for an ordering within the compounds.

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  8. Hi, I meant to post a reply, but I got caught up with work and such. So I guess I will just conclude by thanking you for the discussion, and noting that Feser would probably be in agreement with "Logic is all about the interplay of subject and predicate, ie, singular and general terms, so my physical system must have elements that play these roles."

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