Re: Finding useful functions- part 1

From: Bill Modlin (wdmalias-cap_at_yahoo.com)
Date: 11/05/04 

Date: Thu, 04 Nov 2004 23:22:59 -0500

David Longley wrote:
> In article <+Xqwk5Kq+VhBFwhk@longley.demon.co.uk>, David Longley
> <David@longley.demon.co.uk> writes

< snipped an exchange with Wolf as only marginally related to these
remarks David interjected earlier, or to his current questions: >

>> Not to pre-empt Wolf, but let me remind you of the section on ANNs in
>> "Fragments" <http://www.longley.demon.co.uk/Frag.htm>. What was that
>> all about? What's *wrong* with ANNs? What's wrong with our folk
>> psychology? What's wrong with people?
>>
>> Why are people prejudiced? What's wrong, for instance, with concluding
>> from the -2SD mean IQ of sub-sahara Africa relative to the UK mean, or
>> the -1SD mean IQ of African undergraduates, or USA Afro-Carribeans
>> that blacks are less intelligent than whites and whites are less
>> intelligent than yellows (East Asians)? Is anything missing? If so,
>> can you tell us?

Since David did not include my previous reply I'll paste it here:

---- posted previously ----

David holds that human thinking, that what passes for
"reasoning" in naive human experience, is so terribly
flawed, biased, and generally unscientific that there can
be no value whatever in reproducing it with a machine.

To David, the only imaginable purpose for an AI is to
supplant error-riddled human intensional heuristics with
rational extensional methods. To him, AI *is* the
advancement of extensional science.

Which leads to conflict with those of us who notice that
despite obvious inadequacies of our biological intelligence
in matters of rational estimation and deductive logic, there
are still many things people manage to do quite well, things
people accomplish much more effectively than any machine
we've yet been able to design.

Those of us who find value in natural intelligence would
like nothing better than to emulate it with a machine. To
us, AI is the search for ways to do that, ways to get a
machine to do the things we find so trivially easy. Like
shopping for groceries, or cleaning a house, or following
ambiguous instructions. Without becoming immediately bogged
down in an exponential explosion of combinatorial
possibilities to be evaluated. Without tripping over a
frame problem.

The answer to David's first question, "what's wrong with
ANNs", is that their operation is somewhat analogous to the
operation of our own brains. Oversimplified, incomplete,
but still recognizably similar in some of the ways they
solve problems.

And since our brains clearly use those terrible intensional
heuristics, as David has painstakingly documented for all
the world to see, this makes ANNs irrational, and makes
anyone who takes them seriously a threat to the progress of
humanity. It even makes them despicable and evil, if they
seem to understand the problem and yet knowingly persist in
talking about such nasty things.

Of course, to the rest of us the resemblance of ANN
heuristics to some human methods is what makes them worth
talking about.

David simply is unable to understand that many problems
cannot be addressed without heuristics. He includes quotes
in Fragments that make this point quite well, but manages to
slide past them undaunted, his grail of replacing human
thought with pristine rationality miraculously intact.

The sad part is that David is right about the value of
replacing intuitive judgment with objective measures and
rational statistical analysis in places where the data is
available to support such an effort. He's got a legitimate
point, which probably deserves more attention than it gets
in the flux of politically biased funding schemes. If he'd
stick to that, he might actually do some good. But instead
he falls prey to the biases he decries and overgeneralizes
to the point of obvious irrationality... while steadfastly
resisting any appeal to intuitive notions like common sense
to recognize his error.

Bill Modlin

----- end of pasted material ----

> You notably haven't responded to the second point. There's a profoundly
> critically point within it which you shouldn't worry too much about
> having some difficulty with grasping (though that doesn't mean I will
> tell you). As it is, I suspect you (and many others here) haven't a clue
> what I'm talking about. That's because it's representative of something
> worthy of serious, critical self-analysis, and it *is* something I have
> covered before.

You are right, I haven't a clue as to why you feel IQ scores are
relevant here. Since you won't tell me and said not to worry, I won't.

Personally I feel that enough cultural bias is inherent in such tests to
invalidate comparison across cultural groups. But even if a
"culture-free" IQ test were possible, IQ is only a weak correlate of
the complex of laudatory attributes we call "intelligence", so the
judgmental statements would still be inappropriate.

> In your reply, you assert that I generalise to the point of being
> irrational. That's a very bold assertion, but as stated it's *only* a
> bold assertion (i.e. nefarious rhetoric in my book). As far as I know,
> all that I have said is sound, and to date not refuted (and I don't
> refer to folk in c.a.p, although I would take what Glen, Wolf and
> sometimes even you <g>, seriously). I just try *not* to keep repeating
> the evidence as I've already done so ad nauseam to no avail not to
> mention tedious criticism That's very much my point of course. The
> evidence often doesn't matter because most people behave like idiots and
> don't pick up on it. This is something that many, sadly, are only too
> happy to count on (as I'm sure most folk reading this and thinking about
> their *current* concerns will appreciate)
>
> I think you should state your evidence or make an effort to listen more
> carefully. Assuming that latter, what was wrong with your post? Let's
> see you do you can set an example for less "enlightened" others <g>.

You have presented evidence that human judgment is based on heuristics
which lead to suboptimal results in cases where there is sufficient data
to apply more accurate procedures for comparison. You have also
presented evidence that the biases inherent in these heuristics are
difficult to overcome by education and training, that training in better
methods of reasoning often does not generalize well.

You argue that we should therefore prefer to collect data and apply
well-founded statistical and logical procedures rather than rely on
expert clinical judgment, as that judgment is likely to be biased and
suboptimal. This is a reasonable position.

However, you leap from the reasonable assertion that there are more
accurate procedures which should be used when possible to a conviction
that it is always possible. You assume that these procedures, which you
label "rational", "scientific", and "extensional", are sufficient in
themselves to guide all decision processes, that they can replace naive
intensional heuristic reasoning for all purposes.

Which isn't true. The type of reasoning you recommend depends on
repeatable observations of recurring events, and those do not exist
until discovered by the intensional heuristics of perception.

You focus on what happens after a scientist defines an experimental
protocol, with some objective specification of measurements or
observations to be made. At that point we can collect data and look for
useful relationships among our variables, and at that point it is true
that there are potentially better ways to analyze the information than
naive clinical judgment.

I'm looking at how we get to that point, how we can decide in the first
place that some particular set of observations out of all the
combinatorial explosion of possibilities is indeed worth investigating.

It may be hard for you to see this is as a difficult problem, since you
look at a situation through human eyes, and it is "obvious" that there
are only a few potentially relevant variables involved. There are
skills needed to do a good job of experimental design to be sure you are
measuring what you intended to measure, but you don't see even a
fraction of the vast number of potentially measurable aspects of any
given situation.

You don't have to do any sort of analysis to decide that it is probably
not worth recording the variations in the relative positions of each of
the hairs on a rat's skin as he moves around a skinner box, or noting
the moment-to-moment minute fluctuations in the air pressure and
temperature a millimeter away from an arbitrary point on its
hindquarters. You don't consider such possibilities and reject them,
they simply never arise for consideration in the first place.

This is a good thing. It also turns out to be hard to explain in terms
of purely logical extensional processes, so hard that it is essentially
impossible. This is a facet of what is sometimes known as the "frame
problem", the problem of getting a logical device to focus on the
relevant aspects of a situation without first having to sort through an
infinite regress of irrelevant possibilities.

You solve it effortlessly, without even thinking about it, as part of
your innate perceptual processing. As you examine any situation you
project on it an intensional structure highlighting the probable major
causal focii and their rough relationships... this pushes on that, and
may cause that other thing to topple...

You can do this because you use those intensional heuristics your own
evidence shows to dominate human reasoning. You can do this better than
any system using extensional logic because intensional heuristics are
more appropriate than extensional logic for managing the sort of
information flow available to us through our senses.

We reason using intensional heuristics because they work better than
extensional analysis, in real-life situations characterized by too many
variables and too little information to support extensional analysis.

These heuristics don't give us the accuracy achievable with extensional
procedures under ideal conditions. You focus on that aspect of the
comparison and argue that we should strive to suppress the use of
heuristics, change our way of thinking and speaking to conform to an
extensional ideal.

But your argument is fundamentally misguided, as the two are not
interchangeable. Extensional analysis is impotent for guiding decisions
in the vast majority of situations encountered in the real world. An
organism cannot survive using extensional reasoning alone: heuristic
intensionality is required to deal with the frame problem and reduce the
dimensionality of problems sufficiently to bring them within the scope
of extensional analysis. Extensional analysis is icing on the cake, we
can survive without it. We can't survive without heuristics.

As with humans, so with our constructs. An AI must be constructed first
and foremost to employ intensional heuristics successfully. Once we get
that working, we can add in extensional reasoning as an occasionally
useful overlay.

Bill Modlin

Quantcast