The halting problem has a structural similarity to the Goodman/Kripke paradox insofar as the fact that the machine has not yet halted cannot count as evidence that it will not halt.
Also, the demonstration that a human mind is like a general cognitive engine - a Turing machine - would have to include a demonstration that it was following the rules of such a machine, and Kripke has shown that this demonstration cannot be conclusively constructed.
So, curiously, it seems that if my mind is like a Turing machine, there is no finite way in which I could demonstrate this. It would not be a computable issue.
The proposal that the mind is a kind of Turing machine can only ever be a kind of assumption of cognitive science - a 'false heuristic'? - and not part of a deductive cognitive theory.
Friday, November 25, 2011
Wednesday, November 23, 2011
'Meaning is Use'
We could confuse two views:
(1) If we know how to use a word, then we know it's meaning.
(2) We give the meaning of a word by giving an account of its use.
The first seems unexceptionable.
The second is much more problematic. To give an account, we are already depending upon some un-articulated meaning/uses. Why should some of these be more 'obvious' than others? Why, apart from a specific context of enquiry (a specific question, or specific ignorance) should some be based on others?
Also, we do not learn use meanings from such definitions - although these may aid us in some specific circumstances. We learn them through practice, through experiments with use.
Also, approach (2) is confusing with respect to meaningfulness in general - knowing how to talk preceeds knowing that a certain articulated use of a word is correct. It's perfectly easy to imagine a restricted language game in which the meaning relation didn't exist - in which no accounts of meanings were ever given. As with the 'slab, brick' game, we might construct a theory of the meanings of the words in such a language. But giving a type (2) theory in terms of uses rather than representations does not avoid the difficulty that Wittgenstein used this game to illustrate: we cannot say that the users of the game share our theory of their meanings.
If we play chess with someone who cannot speak, can we say that they are following the rules of chess? Kripke would say: only provisionally, and they might be following any number of other sets of rules which produced congruent behaviour in the games we had actually played with them. Wittgenstein might say that they were not following rules, but just playing chess. And that we might be wrong about that.
When we make a (1) type judgement - that we know how to use a certain word - we are exposed to Kripke's scepticism about what we might mean by it unless we make it in a shared conversation which 'works'. To ask whether this shared conversation might rest upon unrecognised Kripkean ambiguities is to ask whether it is, in fact, a shared conversation - a question which cannot arise within it. When I say 'I know how to talk to you - I know what we mean by what we say', I am not saying something than can be refuted (shown to be false) by some behavioural evidence because a consequence of my being wrong would not be that I had said something false, but that I had not said anything meaningful - and so not anything at all.
So 'meaning is use' turns out to be a warning, not a theory - and, in particular, a warning against the semantic role of type (2) articulations.
(1) If we know how to use a word, then we know it's meaning.
(2) We give the meaning of a word by giving an account of its use.
The first seems unexceptionable.
The second is much more problematic. To give an account, we are already depending upon some un-articulated meaning/uses. Why should some of these be more 'obvious' than others? Why, apart from a specific context of enquiry (a specific question, or specific ignorance) should some be based on others?
Also, we do not learn use meanings from such definitions - although these may aid us in some specific circumstances. We learn them through practice, through experiments with use.
Also, approach (2) is confusing with respect to meaningfulness in general - knowing how to talk preceeds knowing that a certain articulated use of a word is correct. It's perfectly easy to imagine a restricted language game in which the meaning relation didn't exist - in which no accounts of meanings were ever given. As with the 'slab, brick' game, we might construct a theory of the meanings of the words in such a language. But giving a type (2) theory in terms of uses rather than representations does not avoid the difficulty that Wittgenstein used this game to illustrate: we cannot say that the users of the game share our theory of their meanings.
If we play chess with someone who cannot speak, can we say that they are following the rules of chess? Kripke would say: only provisionally, and they might be following any number of other sets of rules which produced congruent behaviour in the games we had actually played with them. Wittgenstein might say that they were not following rules, but just playing chess. And that we might be wrong about that.
When we make a (1) type judgement - that we know how to use a certain word - we are exposed to Kripke's scepticism about what we might mean by it unless we make it in a shared conversation which 'works'. To ask whether this shared conversation might rest upon unrecognised Kripkean ambiguities is to ask whether it is, in fact, a shared conversation - a question which cannot arise within it. When I say 'I know how to talk to you - I know what we mean by what we say', I am not saying something than can be refuted (shown to be false) by some behavioural evidence because a consequence of my being wrong would not be that I had said something false, but that I had not said anything meaningful - and so not anything at all.
So 'meaning is use' turns out to be a warning, not a theory - and, in particular, a warning against the semantic role of type (2) articulations.
Monday, November 14, 2011
Why should we expect unexamined heuristics to be false?
Here are some reasons why they might be:
(1)
Given Nature's indifference between functioning heuristics, and the likelihood that the ratio of successful false heuristics to successful true ones is likely ot be high, the probability that an unexamined heuristic is false must be high.
(2)
There is a sense in which all all language users share a specific false heuristic: that they somehow live in the same world, and that this is why their shared language makes sense. In fact, they only think they live in the same world because their shared language makes sense. It is only in a shared language game that this question can arise, and it is only because the shared language game works that we can sustain the illusion of some pre-linguistic shared world.
(3)
Why would we articulate a tacit heuristic? In normal conversation, this would only happen if a difficulty had arisen: if interlocutors discovered that just pointing to a practice did not resolve a dissonance. In this case, the interlocutors have discovered that they are unintelligible to one another, and need to modify the game to recover.
Except in the case of a simple grammatical or computational error, this process would have to result in at least some interlocutors abandoning heuristics as they articulated them.
(4)
The work of interrogating a heuristic falls outside the discipline the heuristic underpins - settling issues of its truth or falsehood is unlikly to be relevant to the discipline. It might shed light on whether the discipline as a whole made sense, but this is not an issue routinely raised by practitioners, who can point to their own successful (?) practices in support of their intelligibility and who can therefore relegate heuristic 'housekeeping' to philosophers. Their (reasonable) presumption might be that practically inconsequential inconsistencies in the underlying heuristics must be addressable.
An efficient intellectual division of labour would lead to disciplinary heuristics being simplified, since more generally defensible underpinnings would incorporate complexities which were practically irrelevant.
(1)
Given Nature's indifference between functioning heuristics, and the likelihood that the ratio of successful false heuristics to successful true ones is likely ot be high, the probability that an unexamined heuristic is false must be high.
(2)
There is a sense in which all all language users share a specific false heuristic: that they somehow live in the same world, and that this is why their shared language makes sense. In fact, they only think they live in the same world because their shared language makes sense. It is only in a shared language game that this question can arise, and it is only because the shared language game works that we can sustain the illusion of some pre-linguistic shared world.
(3)
Why would we articulate a tacit heuristic? In normal conversation, this would only happen if a difficulty had arisen: if interlocutors discovered that just pointing to a practice did not resolve a dissonance. In this case, the interlocutors have discovered that they are unintelligible to one another, and need to modify the game to recover.
Except in the case of a simple grammatical or computational error, this process would have to result in at least some interlocutors abandoning heuristics as they articulated them.
(4)
The work of interrogating a heuristic falls outside the discipline the heuristic underpins - settling issues of its truth or falsehood is unlikly to be relevant to the discipline. It might shed light on whether the discipline as a whole made sense, but this is not an issue routinely raised by practitioners, who can point to their own successful (?) practices in support of their intelligibility and who can therefore relegate heuristic 'housekeeping' to philosophers. Their (reasonable) presumption might be that practically inconsequential inconsistencies in the underlying heuristics must be addressable.
An efficient intellectual division of labour would lead to disciplinary heuristics being simplified, since more generally defensible underpinnings would incorporate complexities which were practically irrelevant.
Wednesday, November 09, 2011
Pointing to Practices
While we can 'point' to practices which underpin our thought and talk, we should be careful about how we use this in our explanations. In empirical or anthropological explanations, this pointing is possibly helpful and probably harmless.
If we are looking for a justification for the kind of thinking and talking we are doing, then this pointing may not be helpful.
We can be deceived by something here: often we do point to an unquestioned practice in order to 'justify' something, in ordinary talk. I think this is often just to remind an interlocutor of a shared committment, however, so it really only counts as a hypothetical justification: "Remember that X implies Y" is OK if someone has temporarily forgotten the relevance of X and its status as a fundamental. So the form of the argument is: if we are having the conversation I think we are then you must see that Y is unavoidable.
But, of course, it may exactly be X or its relevance that are in play; and there may exactly be confusion over the nature of the conversation. Regress beckons ...
Some might argue, from here, that we should review what we mean by 'justify', to bring it more into line with pointing at shared committments. This move is exposed to an open question objection unless the shared commitments are unavoidable - if they must be shared by anyone having what could count as 'a conversation' at all. In this case, confusion stops the conversation; we have no tools for exploring or explaining it.
If we are looking for a justification for the kind of thinking and talking we are doing, then this pointing may not be helpful.
We can be deceived by something here: often we do point to an unquestioned practice in order to 'justify' something, in ordinary talk. I think this is often just to remind an interlocutor of a shared committment, however, so it really only counts as a hypothetical justification: "Remember that X implies Y" is OK if someone has temporarily forgotten the relevance of X and its status as a fundamental. So the form of the argument is: if we are having the conversation I think we are then you must see that Y is unavoidable.
But, of course, it may exactly be X or its relevance that are in play; and there may exactly be confusion over the nature of the conversation. Regress beckons ...
Some might argue, from here, that we should review what we mean by 'justify', to bring it more into line with pointing at shared committments. This move is exposed to an open question objection unless the shared commitments are unavoidable - if they must be shared by anyone having what could count as 'a conversation' at all. In this case, confusion stops the conversation; we have no tools for exploring or explaining it.
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