Re: Aaron Sloman's "The Irrelevance of Turing Machines to AI" article

From: Neil W Rickert (rickert+nn_at_cs.niu.edu)
Date: 08/02/04 

Date: Mon, 2 Aug 2004 00:59:20 +0000 (UTC)

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Wolf Kirchmeir <wwolfkir@sympatico.ca> writes:
>Neil W Rickert wrote:

>> You are still taking for granted that there is an a priori ability
>> at judging similarity.

>Well, my observations of organisms suggest that this is so. As to "where
>it comes from": Since in children (for example) the ability to
>discriminate smller _dissimilarities_ increases with age, it seems
>reasonable to conclude that the ability "to judge similarity" develops,
>ie, it doesn't "come from" anywhere.

On the one hand you say it is a priori. On the other, you say that
it changes as the child grows. These seem contradictory. And saying
that it doesn't come from anywhere is simply evasive.

> The mechanism is operant
>conditioning in conjunction with changes within the brain, since it
>appears that there is a sequence in the development of different
>discrimination behaviours.

This does not make a lot of sense either. Operant conditioning
already presupposes some notion of similarity, so cannot be used
to explain how that notion is acquired.

> IOW, as the child becomes capable of new
>classes of behaviour, its environment shapes those behaviours in
>specific ways. Eg, language development. Ray Solomonoff's work which
>I've begun to look at, may provide an abstract model of how this
>happens. (Thanks, Eray.)

You responded to my earlier posts with "similarity". You need to
either explain where similarity comes from, or withdraw your comments
on my earlier posts.

>> Where does this ability come from? How are you planning to
>> computationally define it?

>See above.

>Once an organism has responded (however indirectly) to some
>environemntal situation, it will respond the same way to any situation
>that is "similar enough."

Again, you are presupposing that there exists some magical ability to
sense similarity, and you are failing to provide a basis for this
ability. You cannot explain similarity in terms of similarity.

>that is "similar enough." What "the same way" and "similar enough" mean
>will vary from one organism to another, but can be determined
>experimentally. If the system is "plastic" enough, one can train it to
>discriminate smaller _dissimilaritiees_. My sporadic reading in the
>relevant literature indicates that experimenters are wont to ascribe the
>highest "intelligence" to organisms that can be trained to do
>discriminate the smallest differences. Interesting anthropocentrism, that...

>As for "computational definition of similarity", just look at your spell
>checker. It "judges similarity" between the incorrectly spelled word and
>correctly spelled ones.

Poor example. Similarity between words or spellings comes from the
culture. Sure, we form representation of these, and use computation
over representations. But there isn't some grand "similarity"
algorithm in use. It is more a matter of coding lots of rules in an
imperfect attempt to simulate culturally based views of similarity.

>All the same, defining dis/similarity is no easy task.

Right.

So either define it, or stop using it in these discussions. Otherwise
you are calling upon magic which you admit you cannot implement.

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