What is and isn't observable changes over time. Quarks are not in principle unobservable.
Most scientific anti-realists acknowledge this. If quarks become observable then there would be good reason to believe in them. But the mere fact that they are part of an empirically successful theory is not sufficient reason.
Of course, it's unclear whether the observable/unobservable distinction makes sense. Does seeing something through a microscope count as observing it? How about an electron microscope? How about tracks in a bubble chamber?
If quarks become observable then there would be good reason to believe in them.
I hope you mean "if they are actually observed".
But, if we didn't believe (to a degree) in theoretical predictions before making observations to confirm them, then we wouldn't know what observations to attempt, and would almost never actually observe something useful!
Of course, it's unclear whether the observable/unobservable distinction makes sense.
Anchoring on what most humans can observe unaided is just silly. I have acute myopia since age 6; without modern ...
Despite being (IMO) a philosophy blog, many Less Wrongers tend to disparage mainstream philosophy and emphasize the divergence between our beliefs and theirs. But, how different are we really? My intention with this post is to quantify this difference.
The questions I will post as comments to this article are from the 2009 PhilPapers Survey. If you answer "other" on any of the questions, then please reply to that comment in order to elaborate your answer. Later, I'll post another article comparing the answers I obtain from Less Wrongers with those given by the professional philosophers. This should give us some indication about the differences in belief between Less Wrong and mainstream philosophy.
Glossary
analytic-synthetic distinction, A-theory and B-theory, atheism, compatibilism, consequentialism, contextualism, correspondence theory of truth, deontology, egalitarianism, empiricism, Humeanism, libertarianism, mental content externalism, moral realism, moral motivation internalism and externalism, naturalism, nominalism, Newcomb's problem, physicalism, Platonism, rationalism, relativism, scientific realism, trolley problem, theism, virtue ethics
Note
Thanks pragmatist, for attaching short (mostly accurate) descriptions of the philosophical positions under the poll comments.
Post Script
The polls stopped rendering correctly after the migration to LW 2.0, but the raw data can be found in this repo.