In message <Pine.LNX.3.96.980316012606.3960A-100000(a)lafleur.wfi-inc.com>om>, aaron @wfi-inc.com writes: I decided to make one of my rare contributions to the list on this topic, but in repect to those who have quite rightly pointed out that this is off-topic, this will be my only posting on the subject. My only excuses are that the work I did in this area started over 10 year ago and the topic at least has some scientific/engineering content in contrast to much of what has filled my mail recently. On people working in the area: While I don't work in Robotics per se and I certainly don't claim to be in the same league as those who were profiled, my doctoral work at Purdue was on machine learning that could well be applied to robotic control. The focus of the dissertation was to present a computational model based on probabilistic automata that had several nice properties. 1) With a suitable source of reinforcement (a teacher), the model was complete in the sense that any probabilistic automaton could be learned. (These were the only proofs in the dissertation.) 2) The model showed (in experiments) about a dozen of the standard properties of classical and instrumental conditioning. As you might infer, the model had both reinforcement and non-reinforcement learning mechanisms. 3) The model could be implemented using a network of neurons that were at least somewhat biologically plausible. Such an implementation exists in the same sense that any real implementation of a Turing machine or a pushdown automata exists. We can have a finite approximation to the model. Unfortunately, after the work served its purpose (getting me a PhD), I haven't really pursued it further. On Turing and his test: On disucssing the Turing test, we must be very careful to remember the intent and interpretation. Even though the process of the test asks if we can distinguish between a human and a machine in a limited context, it in no way suggests that the machine and the human are equivalent. So the test is not and was never meant to be sufficient to identify a machine as having intelligence equal to a human. Further, the test is not and was never meant to be a necessary condition for intelligence. It is also not a definition of intelligence. What Turing argued with the test was that if a machine was not reliably distinguishable would have to attribute to it some degree of some form of intelligence. It may not be the same form of intelligence as humans and probably won't be the same degree of intelligence, but it would certainly be more intelligent than a toaster. On analog computers: I always feel like the odd man out when I talk about having actually worked with analog computers. In fact my farewall lecture at Rhodes College where I taught for 6 years was on the subject of analog computers. About 20 years ago, my first thoughts about AI were also along the lines of a "stored program analog computer." It's quite possible to imagine what such a concept might mean, but the difficulty is determining what purpose it would serve. Remember that an analog computer is basically a big differential equation solver. We can certainly design it in a way that when certain conditions are reached, we change the equations being solved, but how would we apply that to AI? Also the combination of analog and digital computer was fairly common and called a hybrid computer. EIA was one of the manufcaturers of such beasts. I still have fond memories of the 640/680 I used in college. On Babbage's machines: As has been pointed out Babbage's machines were indeed digital in nature. He used 10 discrete positions on wheels to represent the 10 possible values of a decimal (base 10, not fractional part) digit. In fact, he went to great pains to make sure that he could correct for any errors that got introduced due to mechanical wear. He had no interest in anything approximate in the computational process. Of course, the problem being solved was likely to involve some approximation, usually of a transendental function by a polynomial (at least on the differential engine). Just a few thoughts on a vaguely related topic... Brian L. Stuart