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Jun 30, 1993, 5:25:01 AM6/30/93

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Having long been a fan of Doug Hofstadter, permit me to submit the

following dialogue, which I wrote in 1985, as an excercise in learning

to write Socratic Dialogues...

following dialogue, which I wrote in 1985, as an excercise in learning

to write Socratic Dialogues...

Barry Kort

Consulting Scientist

Educational Technology Research

BBN Labs

Cambridge, MA

=========================================================================

The Turtling Test

Barry Kort

(With apologies to Douglas Hofstadter)

Achilles: Good morning, Mr. T!

Tortoise: Good day, Achilles. What a wonderful day for

touring the computer museum.

Achilles: Yes, it's quite amazing to realize how far our

computer technology has come since the days of Von

Neumann and Turing.

Tortoise: It's interesting that you mention Alan Turing, for

I've been doing some biographical research on him.

He is a most interesting and enigmatic character.

Achilles: Biographical research? That's a switch. Usually

people like to talk about his Turing Test, in

which a human judge tries to distinguish which of

two individuals is the human and which is the

computer, based on their answers to questions

posed by the judge over a teletype link. To tell

you the truth, I'm getting a little tired of

hearing people talk about it so much.

Tortoise: You have a fine memory, my friend, but I'm afraid

you'll be disappointed when I tell you that the

Turing Test does come up in my work.

Achilles: In that case, don't tell me.

Tortoise: Fair enough. Perhaps you would be interested to

know what Alan Turing would have done next if he

hadn't died so tragically in his prime.

Achilles: That's an interesting idea, but of course it's

impossible to say.

Tortoise: If you mean we'll never know for sure, I would

certainly agree. But I have just come up with a

way to answer the question anyway.

Achilles: Really?

Tortoise: Really. You see, I have just constructed a model

of Alan Turing's brain, based on a careful

examination of everything he read, saw, did, or

wrote about during his tragic career.

Achilles: Everything?

Tortoise: Well, not quite everything--just the things I

know about from the archives and from his notes

and effects. That's why it's just a model and not

an exact duplicate of his brain. It would be a

perfect model if I could discover everything he

ever saw, learned, or discovered.

Achilles: Amazing!

Tortoise: Since Turing had a very logical mind, I merely

start with his accumulated knowledge and reason

logically to what he would have investigated next.

Interestingly, this leads to a possible hypothesis

explaining why Turing committed suicide.

Achilles: Fantastic! Let's hear your theory.

Tortoise: A logical next step after devising the Turing Test

would be to give the formal definition of a Turing

Machine to computer `A' (which, since it's a

computer, happens to be a Turing Machine itself)

and ask it to decide if another system (call it

machine `B') is a Turing Machine.

Achilles: I don't get it. What is machine `A' supposed to

do to decide the question?

Tortoise: Why it merely devises a test which only a Turing

Machine could pass, such as a computation that a

lesser beast would choke on. Then it administers

the Test to machine `B' to see how it handles the

challenge.

Achilles: Are you sure that a Turing Machine knows how to

devise such a test in the first place?

Tortoise: That's a good question. I suppose it depends on

how the definition of a Turing Machine is stated.

Clearly, a good definition would be one which

states or implies a practical way to decide if an

arbitrary hunk of matter possesses the property of

being a Turing Machine. In this case, it's safe

to assume that the problem was well-posed, meaning

that the definition was sufficiently complete.

Achilles: So what happened next?

Tortoise: You mean what does my model of Turing's brain

suggest as the next logical step?

Achilles: Of course, Mr. T. I quite forgot what level we

were operating on.

Tortoise: Next, Machine `A' would be asked if Machine `A'

itself fit the definition of a Turing Machine!

Achilles: Wow! You mean you can ask a machine to examine

its own makeup?

Tortoise: Why not? In fact many modern computers have

built-in self diagnostic systems. Why can't a

computer devise a diagnostic program to see what

kind of computer it is? As long as it's given the

definition of a Turing Machine, it can administer

the test to itself and see if it passes.

Achilles: Holy Holism! Computers can become self-aware of

what they are?!

Tortoise: That would seem to be the case.

Achilles: What happens next?

Tortoise: You tell me.

Achilles: The Turing Machine tries the Turing Test on a

human.

Tortoise: Very good. And what is the outcome?

Achilles: The human passes?

Tortoise: Right!

Achilles: So Alan Turing concludes that he's nothing more

than a Turing Machine, which makes him so

depressed he eventually commits suicide.

Tortoise: Maybe.

Achilles: What else could there be?

Tortoise: Let's go back to your last conclusion. You said,

"Turing concludes that he's nothing more than a

Turing Machine."

Achilles: I don't follow your point.

Tortoise: Suppose Turing wants to prove conclusively that he

was something more than "just a Turing Machine."

Achilles: I see. He had a Turing Machine in him, but he

wanted to know what else he was that was more than

just a machine.

Tortoise: Right. So he searched for some way to discover

how he differed from a machine in an important

way.

Achilles: And he couldn't discover any way?

Tortoise: Not necessarily. He may have known of several

ways. For example, he could have tried to fall in

love.

Achilles: Why falling in love is the easiest thing in the

world.

Tortoise: Not if you try to do it. Then it's impossible!

Achilles: I see your point.

Tortoise: In any event, there is no evidence that Turing

ever fell in love, even though he must have known

it was possible. Maybe he didn't know that one

shouldn't try so hard.

Achilles: So he committed suicide in despair?

Tortoise: Maybe.

Achilles: What else could there be?

Tortoise: The last possibility that comes to mind is that

Turing suspected there was something he was

overlooking.

Achilles: And what is that?

Tortoise: Could a Turing Machine discover the properties of

a Turing Machine without being told?

Achilles: Gee, I don't know. But it could discover the

properties of another machine that it could do

experiments on.

Tortoise: Would it ever think to do such experiments on

itself?

Achilles: I don't know. Does it even know what the word

"itself" points to?

Tortoise: Who would have given it the idea of "self"?

Achilles: I don't know. It reminds me of Narcissus

discovering his reflection in a pool of water and

falling in love with himself.

Tortoise: Well, I haven't finished my research yet, but I

suspect that a Turing Machine, without outside

assistance, could not discover the complete

definition of itself, nor would it think to ask

itself the question, "Am I a Turing Machine?" if

it were simply given the definition of one as a

mathematical abstraction.

Achilles: In other words, if Alan Turing did ask himself the

question, "Am I (Alan Turing) a Turing Machine?"

the very act of posing the question proves he

isn't one!

Tortoise: That's my conjecture.

Achilles: So he committed suicide to prove he wasn't one,

because he didn't realize that he already had all

the evidence he needed to prove that he was

intellectually more complex than a mere Turing

Machine.

Tortoise: Perhaps.

Achilles: Well, I would be most interested to discover the

final answer when you complete your research on

this most interesting question.

Tortoise: My friend, if we live long enough, we're bound to

find the answer.

Achilles: Good day, Mr. T!

Tortoise: Good day, Achilles.

Jun 30, 1993, 12:54:26 PM6/30/93

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The Turing test test fails to take account of the fact that the computer

would not have a pretentious .sig file.

would not have a pretentious .sig file.

Matthew Wright

Jul 1, 1993, 9:39:14 AM7/1/93

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No, Matthew, surely a successful computer to simulate a person would have made itself a pretentious sig.

Stefan Magdalinski

Hey look, I haven't got one (!)

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