From newshub.ccs.yorku.ca!ists!helios.physics.utoronto.ca!news-server.csri.toronto.edu!bonnie.concordia.ca!uunet!psinntp!scylla!daryl Tue Jan 28 12:14:58 EST 1992
Article 2954 of comp.ai.philosophy:
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>From: daryl@oracorp.com
Newsgroups: comp.ai.philosophy
Subject: Re: Table-lookup Chinese speaker
Message-ID: <1992Jan21.170056.23347@oracorp.com>
Date: 21 Jan 92 17:00:56 GMT
Organization: ORA Corporation
Lines: 102

Mark Rosenfelder writes:

> Your replies don't address my point, which is that a table-lookup Chinese
> speaker is IN PRINCIPLE impossible.

I think you are wrong, and I think you are provably wrong.

> Now picture a conversation C which fails the Turing test (that is, it's in
> S but not in T).  We can represent C as s(0), s(1), s(2), ..., where these
> are particular statements.

Mark, somehow something is not getting through. I don't require that
the entire conversation be sensible, I only require that the Chinese
Room's responses be sensible. Let me assume that all conversations
begin with the human's statement, and then alternate between human and
Chinese Room.  Then, s(0), s(2), s(4), etc. are statements made by the
human, and s(1), s(3), s(5), etc. are statements made by the Chinese
Room.

The database includes all conversations of less than 100 years in
length such that the Chinese Room's responses are all sensible, and
*no assumption is made about the human's responses*. Since the Chinese
Room is required to respond sensibly to *anything* said by the human,
then if s(0), s(1), ... s(m) is in the database, and s(0), s(1), ...
s(m+1) is not, then either:

a. The conversation s(0), ... s(m + 1) is greater than 100 years in length,
or

b. The last response, s(m + 1), is a response made by the Chinese
Room. (That is, m must be even, and m + 1 is odd.)

Restated, if s(0), ... s(m - 1) is a conversation in the database, and
m is even (so that s(m) is the human's response), then s(0), ..., s(m)
will be in the database, regardless of what s(m) is (even if it is
nonsense, provided it is short enough that the conversation takes less
than 100 years).

Got it?

> There is some number m which is the highest number such that a conversation
> beginning s(0), s(1), ... s(m) exists in T.  (m must be less than the total
> length of the conversation, because we said that C was not in T.)

Fine. By the rules above, that means that either s(0),...s(m + 1) is more
than 100 years in length, or else, s(m + 1) is the Chinese Room's response.

> We can therefore have a conversation with the machine which starts with
> s(0), s(1), ... all the way up to s(m).  The computer can utter s(m) ...

No, by the above reasoning, s(m) is our response, not the computer's.

> However, we now utter s(m+1).

No we don't. It's not our turn! s(m) was our response, and s(m +1) is the
computer's.

> The machine now has no valid response to make. There is no
> conversation in T which begins s(0), ... s(m), s(m+1), since m is the
> *largest* number such that a conversation s(0), ..., s(m), ...  exists
> in T.  Since the machine has no response to make, it fails the Turing
> test.

You have failed to keep track of whose response is response s(m + 1).
If s(0), ... s(m) is in the database, and s(m + 1) is not, then s(m)
was your statement, and s(m + 1) is the Chinese Room's response, and
you can't make it.

Let me make this more precise: Let s(0), s(1), s(2), ... be an arbitrary
conversation in the database. Then:

     s(0): The database includes absolutely every opening statement of less
           than 100 years length, since the opening statement is made by
           the human.

     s(1): This statement is the computer's response. By assumption, it will
           be an appropriate response to s(0).

     s(2): Once again, the database includes absolutely every possibility for
           s(2), since that is the human's move. So, regardless of what
           s(0), s(1), and s(2) were, if s(1) is an appropriate response to
           s(0), then there will be a conversation starting s(0), s(1), 
           s(2), ... in the database.

     s(3): This will an appropriate response to s(2), given that the
           conversation starts out s(0), s(1), s(2).

     s(4): This can be anything at all.

     etc.

So if s(0), ... s(m) is in the database, and s(m + 1) is not, then s(m) was
a response made by the human (not the computer), and s(m +1) is a response
made by the computer.

There is no response *you* can make that can force the conversation
out of the database, except by making a response that is more than
100 years in length.

Daryl McCullough
ORA Corp.
Ithaca, NY


