As you know, I sometimes toy with the idea that the state should not compel people to fund this kind of research if they don't think it's worthwhile. In other words, research could be funded by voluntary contributions, a mixture of rich benefactors, and not-so-rich people voluntarily giving (say) 1% of their income towards research. This could go towards specific areas of research, or be given to RCUK to be distributed as they see fit (and the Haldane principle could become a reality!). That way, if people think astronomy (say) really enriches their lives, and they'd like more of it, then they can express that with their wallets. And my question will answer itself. (See - I'm not completely anti-market!)

But all of that is completely fanciful in the actual world, I suspect.

Still no answer. But academics are meant to ask questions, not find answers, right?

I think that really is the tricky question. Because it's obviously worthwhile to know more about the universe even if the knowledge has no application. But it's also worthwhile to be able to do a whole host of other things we might do with the resources, too: and we can't do all of them!

Direct comparisons are quite invidious, but even in the state-funded sector we could think about education, healthcare and other things which we also think are important. And then, of course, the government has to raise the taxes in the first place, which causes less activity in market sectors of the economy: retail, manufacturing, agriculture and so on. How much of that are we willing to give up for the other stuff? (Especially given that we often can't really choose what precisely it is that we would give up to get the knowledge.)

That's not an answer, but I hope it sharpens the question.