Are committed truthseekers lonelier?

I don't see why truth seekers should have any extra difficulty attracting friends. Truth speakers are a different story.

Perhaps you have conflated correlation and causation. It is possible that loners, or people who are less concerned with group conformity simply have more time and resources to devote to their rationality.

Incidentally, I've lost many friends over the years because I'm far more interested in being rigorous about beliefs and evidence than they are comfortable with.

(This isn't the same thing as seeking truth; I'm usually far more interested in working out what follows from a belief in X than in working out whether a belief in X follows from observable data.)

I've also lost friends because of activities they're really interested in that bore me to tears. These things happen.

But I've also made a great many friends for whom this aspect of my personality is a large part of what they like about me. And I don't regret the trade for a moment.

So when I find myself feeling like I have to choose between being true to myself and having friends, I generally conclude that my best bet is to seek out better friends.

Without resorting to psychology, it seems like one obvious reason why "committed truthseekers" would be lonelier is that committed truthseeking is a time-consuming, often solitary, and rather unpopular activity. Unless you have fairly particular circumstances that permit you to meet other similar minds (e.g. you're in academia or the sciences) your truthseeking time is probably taking away from your socializing time.

Sure; comparative advantage (and sometimes just the belief in comparative advantage) creates polymorphism.

That is, if I identify as a dedicated truthseeker for whom social concerns are a mere distraction, I won't learn social skills or practice them. If I identify as a dedicated socializer for whom the truth is irrelevant, I won't learn rational skills or practice them. That sort of polarizing identification will create the kinds of socially incompetent truthseekers you describe.

But IME an epistemic predisposition for truth over falsehoods (which generally entails such virtues as curiosity and rigor and a willingness to question and so forth) sorts pretty independently with a social predisposition for respecting other people's preferences (which generally entails such virtues as kindness and civility and a willingness to cooperate and so forth).

That is, I know plenty of people like you describe, who have the epistemic predisposition but lack the social one, and therefore end up asserting truths and challenging falsehoods without any consideration for other people's preferences. And you're right, as long as they keep doing that, they don't make many friends.

But I also know plenty of people who lack both, and quite a few people who have the social but not the epistemic, and a few people who have both.

So I am not convinced that people with the epistemic predisposition ("truthseekers") are any less likely to be socially successful than the general population, any more than attractive people are any less likely to be intelligent (or vice versa), any more than if I randomly choose a ball and a stick from two piles of 80 white items and 20 red ones, having a red ball makes me less likely to get a red stick.

That said, there seems to be a strong bias in popular culture towards assuming that they are (in all three cases, and many others)... a kind of belief in the conservation of luck, or something, where doing well in one lottery makes you somehow less likely to do well in others. (This is compensated for by a belief in "winning streaks," but that's less relevant when talking about genetic lotteries.)

Interesting question. I think there's something to this in at least one subset of the phenomenon you discuss: when one's environment is filled with believers in X and "truthseeking" leads one to conclude that belief in X is likely false... loneliness ensues, especially if X is a "hot topic" like a political stance or religion. This has been my experience having all-but-deconverted from Catholicism.

Part of the entire reason I want to try for a meetup in Minnesota, as I said to my brother the other day, is that I need some new friends.

A related hypothesis that came up in the discussion with my brother focused on the difference between Myers-Briggs S vs. N types. N's tend to be open to possibilities, "what ifs" and change, and S's a bit less so -- what I see/know is so, deference to authority figures, etc.. I have no idea if "truthseekers" are of a high N component, but it would interesting to know. Perhaps the loneliness only comes about when the surrounding environment is more rigid, unwilling to update given new evidence, or something similar.

If everyone were happy to examine one's case, discuss the available evidence and related probabilistic reliabilities associated... it would seem that there would be no source for divisiveness and therefore no source for loneliness.

Personally, I haven't found it too difficult to maintain a group of friends, even while fitting many of the descriptions you gave. I am somewhat unusual in that I've had the same group of friends since I was 8 years old. There have been additions to the group, of course, and the degree of closeness between any two of us has varied over the years. In general, though, having such a long history together helps us to be able to interact honestly with each other despite our various different behaviors and preferences (political, religious, academic, etc.).

I have found it difficult to find a romantic partner, though there are confounding factors in that problem (going to a school which is only ~30% female).