Dennett and Kripke on rule following, intentionality, and evolution

Daniel Dennett is the solution to all of life’s problems.

Let me give some context to that statement.

I was first introduced to the arguments Kripke made in his influential book, Wittgenstein on Rules and Private Language, through high school debate.  Kripke’s interpretation of Wittgenstein (from here on, KW) makes an argument that the very concept of a rule is incoherent, and therefore rule-following is logically impossible.  This argument was sometimes used to negate LD resolutions: if the resolution is a moral rule, and the very idea of a rule is incoherent, how can the resolution be affirmed?

Here is a summary of the argument, as I understand it after reading the book:

Take as an example a very simple rule that is supposedly very easy to grasp: addition.  If you attempt to add two numbers that you have never added before (or that no one has ever added before – for the sake of simplicity in the example, lets say that no one has ever taken the sum of numbers higher than 50), you can’t know what the answer should be.  Your previous use of “+” was consistent with addition, but it was also consistent with “quaddition”: “x quus y = x + y, if x,  y < 50.  = 5 otherwise”.  How do you know whether in your previous uses of “+” you meant addition rather than quaddition?  You would have to appeal to some rule (or set of rules).  But that rule is itself composed of terms that have only been used in a finite number of cases, even though they are supposed to apply to an infinite number of cases.  For example, suppose you explain addition in terms of counting – count out x number of beads in a heap, count out y number of beads in a heap, then put the heaps together and count the total number of beads.  The problem is that the concept of counting has only been applied a finite number of times – your behavior is equally consistent with “quounting”: counting normally, except if you combine two heaps each of which contain more than 50 items.  And so on, as every concept or rule is defined in terms of some other concept or rule, which in turn have only been applied in a finite number of cases.  The problem is not (just) epistemological: the problem is not only that you can’t know whether someone else (or even yourself) has followed a given rule or not.  Rather, the problem is logical: if there are an infinite number of answers that are consistent with past behavior, then the meaning of any term is radically undetermined.  We can’t even compare addition and quaddition, as I did earlier, because we don’t know what those concepts mean.  As Kripke writes, “Has not the incredible and self-defeating conclusion, that language is meaningless, already been drawn?” (p. 71)

This should be very unsettling.  I know it was very unsettling to me.  Somehow we are all able to proficiently communicate and follow rules, even though to do so is theoretically impossible.

KW offers a “sceptical [sic] solution” to the rule-following paradox: “A sceptical solution of a sceptical philosophical problem begins on the contrary by conceding that the sceptic’s negative assertions are unanswerable.  Nevertheless our ordinary practice or belief is justified because…it need not require the justification the sceptic has shown to be untenable” (p. 66).

Here is a summary of the skeptical solution:

First, we need an alternative conception of language: “Wittgenstein replaces the question, ‘What must be the case for this sentence to be true?’ by two others: first, ‘Under what conditions may this form of words be appropriately asserted (or denied)?’; and second, given an answer to the first question, ‘What is the role, and the utility, in our lives of our practice of asserting (or denying) the form of words under these conditions?” (p. 73)  This is important because the skeptic is right – there is no fact as to whether you mean plus or quus – so in order for your words to mean something, we must rely on a conception of language that doesn’t depend on statements being truth conditions.

Second, we recognize the obvious: “no one actually hesitates when asked to produce an answer to an addition problem” (p. 87) In practice, we are all capable of following rules and using language.  Of course, this only gets us so far, because the skeptic can always ask, how do you know what you did was correct? Rules are normative, not descriptive.  And so considering the individual in isolation, the skeptic is right that we can attribute no rule to his behavior.

Third, we consider the individual in the context of a community.  It is by comparing the individual’s behavior to that of a relevant community that we can say that an individual follows a rule: “An individual who passes such tests is admitted into the community as an adder; an individual who passes such tests in enough cases is admitted as a normal speaker of the language and member of the community.  Those who deviate are corrected and told (usually as children) that they have not grasped the concept of addition” (p. 92).

Fourth, we describe the language game that a community plays, which consists in three things:

A. Agreement.  “If one person, when asked to compute ‘68 + 57’ answered ‘125’, another ‘5’, and another ‘13’, if there was no general agreement in the community responses, the game of attributing concepts to individuals…could not exist” (p. 96).

B. Form of life.  “The set of responses in which we agree, and the way they interweave with our activities, is our form of life.  Beings who agreed in consistently giving bizarre quus-like responses would share in another form of life” (p. 96)

C. Criteria. “Wittgenstein’s sceptical solution to his problem depends on…checkability – on one person’s ability to test whether another uses a term as he does” (p. 99)

Finally, we can concisely explain the solution.  Kripke writes:

“One must bear firmly in mind that Wittgenstein has no theory of truth conditions – necessary and sufficient conditions – for the correctness of one response rather than another to a new addition problem.  Rather he simply points out that each of us automatically calculates new addition problems (without feeling the need to check with the community whether our procedure is proper); that the community feels entitled to correct a deviant calculation; that in practice such  deviation is rare, and so on.  Wittgenstein thinks that these observations about sufficient conditions for justified assertions are enough to illuminate the role and utility in our lives of assertion about meaning and determination of new answers.  What follows from these assertability conditions is not that the answer everyone gives to an addition problem is, by definition, the correct one, but rather the platitude that, if everyone agrees upon a certain answer, then no one will feel justified in calling the answer wrong” (p. 111-112)

I don’t know about all of you, but this solution felt a little fuzzy to me when I first read it.  Not only that, the skeptical solution “does not allow us to speak of a single individual, considered by himself and in isolation, as ever meaning anything” (p. 68-69).  So I was a little flustered.  Lucky for me, Daniel Dennett has my back.

At first I thought that KW’s paradox was only about rules and rule-following.  But after reading the book, I realize that the argument is about meaning: how can a person ever mean one thing rather than another? Philosophers have a word for this: intentionality, the ability of the mind to be “about” something, represent something, mean something.  So I opened my copy of Dennett’s book on intentionality, The Intentional Stance, and looked for “Kripke” in the index, and found some very helpful commentary.

In Dennett’s view, there is a huge dividing line in the philosophy of intentionality: the line between those who do, and those who don’t, make a big fuss about the difference between original or intrinsic intentionality and derivative intentionality.  Dennett (quoting another author, Haugeland) explains the distinction: Artifacts “only have meaning because we give it to them; their intentionality, like that of smoke signals and writing, is essentially borrowed, hence derivative.  To put it bluntly: computers themselves don’t mean anything by their tokens (any more than books do) – they only mean what we say they do.  Genuine understanding, on the other hand, is intentional ‘in it’s own right’ and not derivatively from something else” (p. 289).  In Dennett’s view, this distinction is bogus, and a lot of philosophical problems would be dissolved if we gave it up.  To illustrate this, he provides a thought experiment, The Case of the Wandering Two-Bitser.

“Consider a standard soft-drink vending machine, designed and built in the United States, and equipped with a transducer device for accepting and rejecting US quarters.  Let’s call such a device a two-bitser.  Normally, when a quarter is inserted into a two-bitser, the two-bitser goes into a state, call it Q, which ‘means’ (note the scare-quotes) ‘I perceive/accept a genuine US quarter now.’  Such two-bitsers are quite clever and sophisticated, but hardly foolproof.  They do ‘make mistakes’ (more scare-quotes).  That is, unmetaphorically, sometimes they go into state Q when a slug or some other foreign object is inserted in them, and sometimes they reject perfectly legal quarters – they fail to go into state Q when they are supposed to…The only thing that makes the device a quarter-detector rather than a slug-detector or quarter-or-slug detector is the shared intention of the device’s designers, builders, owners, users.  It is only in the environment or context of those users and their intentions that we can single out some of the occasions of state Q as ‘veridical’ and others as ‘mistaken.’  It is only relative to that context of intentions that we could justify calling such a device a two-bitser in the first place” (p. 290-291).

Now, Dennett says, imagine that a two-bitser is installed on a vending machine in Panama, where  it accepts and rejects “quarter balboas, legal tender in Panama, and easily distinguished from US quarters by the design and writing stamped on them, but not by their weight, thinkness, diameter or material composition…In this new environment, US quarters count as slugs, inducers of error, misperception, misrepresentation…Once our two-bitser is resident in Panama, should we say that the state we used to call Q still occurs? The physical state in which the device ‘accepts’ coins still occurs, but should we now say that we should identify it as ‘realizing’ a new state, QB, instead?” (291-292)

Dennett continues.

“We can assure ourselves that nothing intrinsic about the two-bitser considered narrowly all by itself and independently of its prior history would distinguish it from a genuine q-balber, made to order on commission from the Panamanian government.  Still, given its ancestry, is there not a problem about its function, its purpose, its meaning, on this first occasion when it goes into the state we are tempted to call Q?  Is this a case of going into state Q (meaning ‘US quarter here now’) or state QB (meaning ‘Panamanian quarter-balboa here now’)?  I would say…that whether its Panamanian debut counts as going into state Q or QB depends on whether, in its new niche, it was selected for its capacity to detect quarter-balboas – literally selected, e.g., by the holder of the Panamanian Pepsi-Cola franchise.  If it was so selected…its first ‘perceptual’ act would count as a correct identification by a q-balber, for that is what it would now be for…If, on the other hand, the two-bitser was sent to Panama by mistake, or if it arrived through sheer coincidence, its debut would mean nothing, though its utility might soon – immediately – be recognized and esteemed by the relevant authorities…and thereupon its subsequent states would count as tokens of QB.

Presumably Fodor et al. would be content to let me say this, since, after all, the two-bitser is just an artifact.  It has no intrinsic, original intentionality, so there is no ‘deeper’ fact of the matter we might try to uncover.  This is just a pragmatic matter of how best to talk, when talking metaphorically and anthropomorphically about the states of the device.

But we part company when I claim to apply precisely the same morals, the same pragmatic rules of interpretation, to the human case.  In the case of human beings (at least), Fodor and company are sure that deeper facts do exist – even if we cannot always find them.  That is, they suppose that, independently of the power of any observer or interpreter to discover it, there is always a fact of the matter about what a person (or a person’s mental state) really means

I part company with these others because although they might agree with me…about what one should say in the case of the transported two-bitser, they say that we human beings are not just fancier, more sophisticated two-bitsers” (p. 293-294).

Dennett goes on to point out what should be obvious: just as a two-bitser’s or a computer’s intentionality is derivative (from a human engineer) so too is our own intentionality derivative: it derives from evolution.  We are artifacts of Mother Nature just as much as books are artifacts of authors.  “You are, after all, just a product of natural selection, whose intentionality is thus derivative and hence potentially indeterminate” (p. 313).


Thinking about it this way made things much clearer for me.  Here is how I thought of the skeptical solution after reading Dennett: a person’s functional ability to do addition, or use language, or whatever else, was never in doubt, just as the two-bitser’s functional ability to detect quarters was never in doubt.  The problem was that no person really means addition or whatever, just as the two bitser doesn’t really mean that a quarter or a quarter balboa has been detected.  But the idea that a person, considered in isolation, could really mean something (as opposed to just functionally mean something), is as nonsensical as thinking that a two-bitser considered in isolation “really” means something.  However, we can make sense of a normative conception of meaning by appealing to a shared set of intentions and practices in a community, for a two-bitser or for a human being.

It’s not that Dennett thinks that Kripke is wrong – rather, Dennett thinks that if Kripke (and others) would abandon the distinction between original and derivative intentionality, the skeptical solution would be obvious and intuitive.  Therefore Dennett is able to write, “Kripke’s ruminations on rule-following, which strike some philosophers as deep and disturbing challenges to their complacency, have always struck me as great labors wasted in trying to break down an unlocked door” (p. 294).

It is continually amazes me how one man could be so unbelievably brilliant.

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One Response to Dennett and Kripke on rule following, intentionality, and evolution

  1. chesleya says:

    There’s a great quote in Hofstadter’s essay “The Coffeehouse Conversation” in “The Mind’s I”: “Cash registers can’t really calculate; they can only spin their gears. But cash registers can’t really spin their gears either; they can only follow the laws of physics… People can’t really calculate; all they can do is manipulate mental symbols. But they aren’t really manipulating symbols; all they are doing is firing various neurons in various patterns. But they can’t really make their neurons fire; they simply have to let the laws of physics make them fire for them” (Hofstadter and Dennett 1981, 75-76).

    Hofstadter attributes this quote to Dennett in Brainstorms, but I can’t find the original quote. Anyway, we talked about intentionality extensively in my Philosophy of AI class and I quickly came to the conclusion that it’s total bollocks. John Searle is probably the greatest philosopher on the opposite side of the “diving line”. And he says things like thinking in the “relevant literal sense” and talks about how we attribute intentionality to dogs but not robots. It’s dumb stuff.

    I think this is a great attribution of intentionality (or the lack thereof) to this Kripke argument. I don’t totally buy Kripke’s argument in the first place because for some reason, it reminds me of Zeno’s paradox. Whatever. Great post, Brian.

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