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SUBJECT:  ANALYSIS OF POSITION PAPER 5	
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I have finished grading your Position Papers #5.

I was really hoping that by now all of you would have learned how to
identify and analyze an argument, and to use the terminology correctly.

Many of you have.  But some of you haven't :-(

The grades ranged from 6-30 points (D to A), with an average of 22 (B-).

Most of you clearly identified and listed the premises and conclusions
of the two arguments, but some of you missed one or two premises, and
some of you did not list them, referring only to "premise one" but not
telling me what it was.

There were different ways to identify premises and conclusions; 
here's one way:

Pro:
P1.  x is cognitive iff x can perceive, has BDI, can remember,
			can use natural language, can reason & decide,
			etc.

P2.  If x [merely] behaves as if x were cognitive,
	then x [really] *is* cognitive

	DIGRESSION:  Several of you didn't use Pro's words exactly,
	interpreting them in different ways.  That's always a risky
	thing to do when trying to understand what someone means,
	because you might be misinterpreting them.  For instance,
	some of you thought that this premise was that if x
	"demonstrates" perception, BDI, etc., then x "demonstrates"
	cognition.  But Pro didn't use that word "demonstrate".

P3.  A computer running a suitable AI program will eventually behave
	as if it were cognitive.

	DIGRESSION:  Many of you omitted this.  Omitting it makes
	the argument invalid.

P4.  Therefore, a computer running a suitable AI program will *be*
	cognitive.

A word on terminology:  This argument has 4 "statements".  The first
three (P1,P2,P3) are "premises".  P4 is the "conclusion".  You can't
say, as some of you did, that "premise 4 is a conclusion".  A statement
in an argument is either a premise or else a conclusion of that
argument; it can't be both.  It also makes no sense to talk about the
"fourth conclusion".  This argument only has one conclusion, which is,
indeed, the fourth *statement*.

As I've reconstructed this argument, premise 1 is irrelevant to its
validity (though it may help in deciding whether the other statements
are true or false).

The argument from P2 and P3 to P4 is valid:  P2 has the form:

If x has a property R (R = behaving cognitively),
then x has a property Q (Q = being cognitive)

	DIGRESSION:  The word is "cognitive", not "cognizant" :-)
	"Cognizant" means something like "aware (of)".

P3 has the form:

Something (namely, a certain computer) has property R.

It follows validly that that "something" (i.e., that computer) must have
property Q.

If you're not convinced, think of it this way:

P1 says that all things that are R are also Q. (R is a subset of Q)
P2 gives you something that is an R. (c is a member of R)
So, it must be a Q. (c is a member of Q)

For what it's worth, P2 is a very strong form of the Turing test.
Turing himself wouldn't agree with it:  He was more subtle, and would
only have said that if something behaved as if it were cognitive,
*and if you called it "cognitive"*, then, eventually, no one would
disagree with you.  That's a much weaker claim.

Con's argument:
C1.  x is syntactic iff x is a formal-symbol-system manipulator.
C2.  Computers and programs are syntactic.
C3.  Cognition is semantic
C4.  Syntax does not suffice for semantics

	DIGRESSION:  Many of you missed this premise.  But the
	argument is invalid without it.

C5.  Therefore, no computer executing a syntactic program can be
	semantically cognitive.
C6.  That is, it's not the case that P4

This argument is valid; C1 is irrelevant to the validity.
The argument from C2,C3,C4 to C5 is valid because it has this form:

C2:  Certain things have property R (R = being syntactic)
C3.  Certain other things have property Q (Q = being semantic)
C4.  If x is syntactic, then x is not semantic
	i.e., if x has property R, then x does not have property Q
C5.  Therefore, the things in C2 that have property R don't have property Q.

This is valid for the same reason that Pro's argument is valid.

As many of you noticed, this is Searle's Chinese Room argument.