Sure, maybe we'd see huge pragmatic gains after everyone was (for example) an atheist for a century but there just aren't smaller gains to be realized from atheism at smaller scales.
My inclination is to distrust anyone who claims that the theory they advocate can only be tested by an apparatus too impractical to build, and is necessarily untestable on any scale small enough to actually test... but I concede that it's possible.
And agreed that my examples aren't good analogies for that sort of situation.
This thread has produced some interesting commentary around whether philosophers actually want to answer their own questions, or whether they enjoy sounding profound by debating big questions but don't want to lose that opportunity for profundity by finding single correct answers to them.
I don't quite disagree with the latter theory: the main reason I quit academic philosophy was exasperation that people were still debating questions where the right answer seemed obvious to me (like theism vs. atheism, or whether there was a universally compelling morality/aesthetics of pure reason), and worry that my philosophical career would involve continuing to debate these issues ad nauseum rather than helping to solve them and move on to the next problem.
But when I explained this to a particularly sarcastic friend, he summarized it as "So you think philosophy is useless because not everyone agrees with you?"
The problem isn't that philosophers never come up with solutions. The problem is that they come up with too many different solutions.
Science has solved many scientific problems, and anyone wondering what the solution is can look it up in a book or on Wikipedia. Philosophers have also solved many philosophical problems, but it is full of so many distractions and false solutions that anyone wondering which proposed solution is correct will have to become nearly as good a philosopher as the person who solved it in the first place. It's much easier for science to settle its disputes via experiment than for philosophy to settle its disputes via debate.
I am wary of criticizing the discipline of philosophy simply on the grounds that not everyone in it agrees with me. But I also don't want to let it off and say it's okay that they've managed to go so long without coming to any answers, when it seems to me that settling at least some of the easier problems is not that difficult.
How do we tell the difference between a discipline that doesn't really seek answers and a discipline which honestly seeks answers but just can't agree within itself? And how can philosophy do something about its level of internal disagreement without having to apply the "kick out everyone who disagrees with Less Wrong" solution?