> Well, that's all a lot of nonsense.
I really love it when people start arguments this way. You take the right to refute just about all the things that s/he claimed, but in reality only address at most one.
> One of the more hilarious traits that most programmers seem to share is their belief that they can logically deduce what's true and what's not in fields in which they don't even know the basics.
I think you're jumping to conclusions too early. How did you assess that it's most programmers that share this trait?
Remember, this is Hacker News. Really, there's a plant called Living Stone, and it obviously isn't a stone, but in my experiences, the conversation and ideas presented and discussed here are way different from most other conversations, so I tend to conclude that there are many people contributing to HN that are in an essential way very similar to me, if not ideologically, they certainly are on levels of intellect and curiosity. So I'd say that it's far away from the general programmer. Many, if not most of the programmers (I can't really say, because my sample has been to small and biased to confirm general conclusions, which I intuitively feel are true) are just that - programmers. It's their day job, one they perform, rather mechanically. While programming is certainly a skill unlike any other, and thus learning programming gives you some new, unique knowledge, it doesn't necessarily make you a great, independent, provoking, curious thinker.
Also, I am guessing that the reason that HN seems to be dominated by programmers is simply that internet/forums are the medium of choice for many programmers (familiarity&convenience). I'm positive that there are many other groups of equally inspiring people from completely different professions, having similar conversations.
> Given that every major field of study that I'm aware of has aspects which are hotly debated by that field's experts.
From what I see, hot debates = flamewars are more popular in the general population, particularly in politics, than in academic/expert circles. Flamewars occur when debates are ego-, not truth-based. When people want to win, not to find the truth (or achieve any other, external/impersonal given objective). Again, can't speak for all fields of knowledge, but (1) in mathematics, from what I've experienced, people are mostly interested in research. Ideas are usually merited by how powerful/broad they are, and by how simple and elegant/beautiful they are. Sometimes, one particular idea wins over the others (e.g. measure theory as the basis of probability), othertimes, multiple ideas are found useful (e.g. Riemann/Darboux integral, or Itô/Stratonovich stochastic integral). (2) In physics, ideas are merited based on how well they can predict experimental results, and the only debates happening are where there simply isn't no correct/experimentally confirmed theory yet. Furthermore, everyone acknowledges that any and all theories are necessarily incomplete, and improvements are possible, even expected (e.g. Newton -> Einstein). I'm less familiar with soft sciences, but from what I've seen, in e.g. (3) psychology, many different ideas and explanations coexist, because they each have certain predictive/explanative potential.
People in the general public, on the other hand, usually just hear bits and pieces from one field of knowledge, and then assume that they know everything, or that that single idea is necessarily the best. An expert, on the other hand, has a broader overview of the field and can see that even conflicting ideas can complement each other and be useful when considered together.
> So, if you know nothing -- or little -- about the practical and theoretical complications and possibilities of space travel
I know almost nothing about space travel, but still I believe that there are huge complications and it's improbably in the near future. I can make such conclusions from simple everyday facts (if we haven't accomplished it yet, it probably means that it's hard or very expensive), observations (meteors -> there are rocks flying in space that burn in the Earth's atmosphere -> spaceships have no atmosphere -> ships might be endangered by space rocks) and basic knowledge (Newton's laws => besides accelerating to acceptable speeds, ships must be able to decelerate as well - not that this is a huge problem per se, but it makes space travel a bit more complicated, and it's a fact most people don't consider). That being said, I am perfectly willing to admit, I hope to actually, that I'm wrong, either by experts or by the technological advancement. However, I would never ever ever trust an expert, no matter what his formal and anecdotal qualifications are, if s/he weren't able to convincingly (=with logically sound arguments) address the above considerations.
> Asking someone about their expertise doesn't mean I'm not thinking
Beforehand, it makes sense to ask an expert - they are, we usually assume, trusted by a lot of people, which is an implicit signal that we can trust them as well. However, afterwards, it is an intellectual imperative to consider and reconsider her/his arguments based on logical merit, not on credentials. I.e., an expert could still lie. Asking an expert is useful for expanding knowledge, not informing an opinion. But then, it really makes no sense to hold prejudice against knowledge you can get from other people, simply because they aren't formally experts.