AI and cognitive psychology rant (was Re: BIG successes of Lisp...)

Alex Martelli aleax at
Tue Oct 14 03:45:40 EDT 2003

Stephen Horne wrote:
> I remember the context where I first encountered Bayes theorem. It was
> in AI - expert systems, to be precise - along with my first encounter

OK, but Reverend Bayes developed it well before "AI" was even conceived,
around the middle 18th century; considering Bayes' theorem to be part
of AI makes just about as much sense as considering addition in the
same light, if "expert systems" had been the first context in which
you had ever seen numbers being summed.  In the '80s, when at IBM
Research we developed the first large-vocabulary real-time dictation
taking systems, I remember continuous attacks coming from the Artificial
Intelligentsia due to the fact that we were using NO "AI" techniques --
rather, stuff named after Bayes, Markov and Viterbi, all dead white
mathematicians (it sure didn't help that our languages were PL/I, Rexx,
Fortran, and the like -- no, particularly, that our system _worked_,
the most unforgivable of sins:-).  I recall T-shirts boldly emblazoned
with "P(A|B) = P(B|A) P(A) / P(B)" worn at computational linguistics
conferences as a deliberately inflammatory gesture, too:-).

Personally, I first met Rev. Bayes in high school, together with the
rest of the foundations of elementary probability theory, but then I
did admittedly go to a particularly good high school; neither of my
kids got decent probability theory in high school, though both of
them met it in their first college year (in totally different fields,
neither of them connected with "AI" -- financial economics for my
son, telecom engineering for my daughter).

> Funny how a current popular application of this approach (spam
> filtering) is not considered to be an expert system, or even to be AI
> at all. But AI was never meant to be in your face. Software acts more

I don't see how using Bayes' Theorem, or any other fundamental tool
of probability and statistics, connects a program to "AI", any more
than using fundamental techniques of arithmetic or geometry would.


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