In the early 1980s Douglas Lenat wrote EURISKO, a program Eliezer called "[maybe] the most sophisticated self-improving AI ever built". The program reportedly had some high-profile successes in various domains, like becoming world champion at a certain wargame or designing good integrated circuits.
Despite requests Lenat never released the source code. You can download an introductory paper: "Why AM and EURISKO appear to work" [PDF]. Honestly, reading it leaves a programmer still mystified about the internal workings of the AI: for example, what does the main loop look like? Researchers supposedly answered such questions in a more detailed publication, "EURISKO: A program that learns new heuristics and domain concepts." Artificial Intelligence (21): pp. 61-98. I couldn't find that paper available for download anywhere, and being in Russia I found it quite tricky to get a paper version. Maybe you Americans will have better luck with your local library? And to the best of my knowledge no one ever succeeded in (or even seriously tried) confirming Lenat's EURISKO results.
Today in 2009 this state of affairs looks laughable. A 30-year-old pivotal breakthrough in a large and important field... that never even got reproduced. What if it was a gigantic case of Clever Hans? How do you know? You're supposed to be a scientist, little one.
So my proposal to the LessWrong community: let's reimplement EURISKO!
We have some competent programmers here, don't we? We have open source tools and languages that weren't around in 1980. We can build an open source implementation available for all to play. In my book this counts as solid progress in the AI field.
Hell, I'd do it on my own if I had the goddamn paper.
Update: RichardKennaway has put Lenat's detailed papers up online, see the comments.
I have found Haase's thesis online. Would it be irresponsible of me to post the link here? (It is not actually hard to find.)
ETA: How concerned should we be that DARPA is going full steam ahead for strong AI? Perhaps not very much, given the failure of at least two of their projects along these lines:
High Yield Cognitive Systems. The Wikipedia article (itself defunct) includes the grandiose claim that it failed because human-level AI was not ambitious enough.
Biologically-Inspired Cognitive Architectures. Abandoned.
Physical intelligence. Current.
There are a number of DARPA and IARPA projects we pay attention to, but I'd largely agree that their approaches and basic organization makes them much less worrying.
They tend towards large, bureaucratically hamstrung projects, like PAL, which the last time I looked included work and funding for teams at seven different universities, or they suffer from extreme narrow focus, like their intelligent communication initiatives, which went from being about adaptive routing via deep introspection of multimedia communication and intelligent networks, to just bein... (read more)