Most transhumanist ideas fall under the category of "not even wrong." Drexler's Nanosystems is ignored because it's a work of "speculative engineering" that doesn't address any of the questions a chemist would pose (i.e., regarding synthesis). It's a non-event. It shows that you can make fancy molecular structures under certain computational models. SI is similar. What do you expect a scientist to say about SI? Sure, they can't disprove the notion, but there's nothing for them to discuss either. The transhumanist community has a tendency to argue for its positions along the lines of "you can't prove this isn't possible" which is completely uninteresting from a practical viewpoint.
If I was going to depack "you should get a PhD" I'd say the intention is along the lines of: you should attempt to tackle something tractable before you start speculating on Big Ideas. If you had a PhD, maybe you'd be more cautious. If you had a PhD, maybe you'd be able to step outside the incestuous milieu of pop sci musings you find yourself trapped in. There's two things you get from a formal education: one is broad, you're exposed to a variety of subject matter that you're unlikely to encounter as an autodidact; the other is specific, you're forced to focus on problems you'd likely dismiss as trivial as an autodidact. Both offer strong correctives to preconceptions.
As for why people are less likely to express the same concern when the topic is rationality; there's a long tradition of disrespect for formal education when it comes to dispensing advice. Your discussions of rationality usually have the format of sage advice rather than scientific analysis. Nobody cares if Dr. Phil is a real doctor.
It's interesting that you mention Rodney Brooks. I've always found his work poorly written and lacking in clarity despite being sympathetic to his views. He must come across better in person. As Shane points out though, Brooks' work has the rare quality in AI that it is productive and has found widespread application in industry.
As for the Venture Capitalists, I don't find it surprising that Silicon Valley VCs share some of your interests. It's like discovering that software engineers share an interest in AD&D and collectibles. All these guys are enthusiastic about evolutionary psychology and cognitive science and such. I wonder if your perception of competence is a product of the "keyword search" approach to assessing other people that you frequently apply here; if they mention "evolution" and "probability" enough they get to be smart.
Most sane and intelligent people with religious tendencies (and there are many, although they don't seem to get much press) understand that if "god" means anything, it is a pointer towards something unknown and perhaps unknowable, and arguing about whether it exists in the physical sense is missing the point completely.
This is just a version of my second option available to the theist. There's a knowable "physical" world and an unknowable one beyond it. There's no reason to believe this is the case. Moreover, if you believed something like this, you would be able to say "I'm an atheist about the physical world" and we could all agree on that and discuss whether talk of "something beyond the physical world" is coherent. You would also agree that science has established atheism about the physical world. Which is just my claim.
Matthew C. - I'm referring to neuroscience.
This is why I claim that atheism is an established scientific result. One of the strongest lines of evidence is, indeed, that we have successfully reduced minds and shown the notion of an irreducible mind to be incoherent. Mind as an irreducible simple is basic to all monotheistic religions. Demonstrating something once thought coherent to be incoherent is, of course, one of the strongest lines of evidence in science. Other avenues through which atheism has been established by science include conservation in physics, chemistry and biology (which led directly to materialism), evolution, and the development of plausible sociological accounts of religion. I would argue that atheism is as well established as Plate Tectonics and Natural Selection. What I think is telling is that most contemporary approaches to religious apologetics implicitly recognize that science has established atheism.
The theist has three avenues of response. The first is to attack specific parts of science. This is what Fundamentalist Christians do. The second, by far the most popular, is to attack the very possibility of scientific knowledge. This is what nearly all "liberal" religious believers who claim there is no conflict between science and religion do. They generally adopt a skeptical epistemology, holding that no knowledge claim can be true, or instrumentalism about science, holding that scientific claims are nonfactual, or a quasi-Kantian constructivist metaphysics wherein "true" reality is forever out of reach. The weird thing is that this position, which essentially rejects all of science, is considered more "sophisticated" and acceptable than the Fundamentalist position which rejects only select parts of science but remains realist about the rest. The third approach is to adopt some sort of nonfactualism about religious claims; essentially to hold that your religious practice is merely tradition. I think this nearly exhausts contemporary positions on religious apologetics and is therefore evidence that people implicitly accept that science has established atheism.
It's true that contemporary philosophy is still very much obsessed with language despite attempts by practioners to move on. Observation is talked about in terms of observation sentences. Science is taken to be a set of statements. Realism is taken to be the doctrine that there are objects to which our statements refer. Reductionism is the ability to translate a sentence in one field into a sentence in another. The philosophy of mind concerns itself with finding a way to reconcile the lack of sentence-like structures in our brain with a perverse desire for sentence-like structures. But cognitive science is itself a development of this odd way of thinking about the world; sentences become algorithms and everything carries on the same. I don't think you're really too far removed from this tradition.
If you look through a microscope you'll notice the only major difference between the nervous system and other tissues is that the nervous system exhibits network connectivity. Cells in tissues are usually arranged in such a way that they only connect to their nearest neighbor. Many tissues exhibit electrical activity, communication between cells, coordinated activity, etc, in the same way as neurons. If networks of neurons can be said to be performing computations then so can other tissues. I'm not familar with the biology of trees but I don't see why they couldn't be said to be 'thinking' if we're going to equate thinking with computation.
This demonstrates quite nicely the problem with the magical notion of an "internal representation." (Actually, there's two magical notions, since both "internal" and "representation" are separately magical.) You could easily replace "internal representation" with "soul" in this essay and you'd get back the orthodox thinking about humans and animals of the last two thousand years. Given that there is both no evidence nor any chance of evidence either for "internal representations" or "souls" and neither is well-defined (or defined at all), you might as well go ahead and make the substitution. This entire essay is pure mysticism.
It's not clear that you're a verificationist but you're clearly an Empiricist. I think that's problematic. Unless you believe something magical happens at the retina, then there's no more reason to privilege what happens at the retina or in the brain, than there is the wire connecting the dial to the voltmeter. It's all causal linkage. We can use the same standards of reliability for people as we do wires. The sensory periphery is just not particularly interesting.
Whatever views his belief may be compatible with, it is not compatible with reality. That is, it is false. Intentionality is explainable in physical terms. An intention is the reference signal of a control system, and a control system is something that acts so as to maintain a perceptual signal close to its reference signal.
Everybody has a pet theory of intentionality. The problem isn't intentionality but why anybody would want to explain intentionality in the first place. You're either explaining: (a) a part of what you take to be your experience of the world; or (b) a part of our folk psychological explanations of behavior. Either way, you're not doing science to begin with, so it's unlikely you'd stumble upon science along the way.
Methodological behaviorism took private mental events to be off limits but (most) behaviorists still believed they existed. Skinner took introspection and self-knowledge to by types of behavior and explicitly denied the mental. Eliezer's analysis is correct insofar as Skinner denied the mental but the passages about not being able to account for complex behavior are wrong. Skinner took behavior to be a product of environmental conditioning and evolved physiology.
Here's Skinner explaining radical behaviorism in the opening of About Behaviorism:
"Mentalism kept attention away from the external antecedent events which might have explained behavior, by seeming to supply an alternative explanation. Methodological behaviorism did just the reverse; by dealing exclusively with external antecedent events it turned attention away from self-observation and self-knowledge. Radical behaviorism restores some kind of balance. ... It does not call these events unobservable, and it does not dismiss them as subjective. It simply questions the nature of the object observed and the reliability of the observations."
(Note how similar the final sentence is to eliminativists like Chruchland and Dennett who emphasize that introspection is fallible.)
"The position can be stated as follows: what is felt or introspectively observed is not some nonphysical world of consciousness, mind or mental life but the observer's own body. ... An organism behaves as it does because of its current structure, but most of this is out of reach of introspection."
"[W]e can look at those features of behavior which have led people to speak of an act of will, of a sense of purpose, of experience as distinct from reality, of innate or acquired ideas, of memories, meanings, and the personal knowledge of the scientist, and of hundreds of other mentalistic things or events. Some can be 'translated into behavior,' others discarded as unnecessary or meaningless." (Emphasis mine.)
Skinner was essentially an eliminative materialist who relied too heavily on the tools of his time (operant conditioning). He denied that the brain had the structure of folk psychology (what the behaviorists called mentalism) and emphasized conditioning and evolved physiology (he talked about evolution explicitly).