But, do most LW'ers think that it should be everyone's position?

I won't presume to speak for most LWers.
Speaking for myself, I think we would all be better off if more people's beliefs were more contingent on mutually observable events. So, yeah.
I could be wrong, but I'd love to see the experiment done.

(A meta remark: The usual way to quote another person's post here is to prefix lines with the > character, not to use quotation marks.)

Point taken. The phrase "most dangerous" iis hyperbolic. No, so far I don't see any Less Wrongers blowing up buildings or committing mass murders.

Of which I am very glad.

But, what is it that drives people to do such things? Is it as simple as, "God told me to do this?" I don't think it's usually that simple. I'm not sure what drives it, but I think that part of it is a basic human tendency to divide people up into groups of "we" and "they."

Tribalism is powerful and problematic indeed. But I'm not convinced that tribalism alone is sufficient to create eliminationism — here borrowing Daniel Goldhagen's term for the belief that it is morally right and necessary to exterminate the Other. There are lots of places in the world where distinct tribes coexist, maintaining us/them distinctions, without massacring each other constantly.

So there must be something else involved.

Most of us construct this kind of division to some degree, whether we realize it or not, but fundamentalists take it to the extreme.

It isn't really clear to me that all the things that we might label "fundamentalism" are really the same social phenomena. Sociologically, there may be different things going on in Fundamentalist Protestantism (the trope namer); in theocratic regimes such as Iranian Shia or Saudi Wahhabism; in medieval Catholicism in its persecution of the Cathars, Albigensians, and conversos — and for that matter in the Stalinist purges or other "secular" "fundamentalisms".

Tribalism may be part of it; but doctrinal intolerance — the notion that people who believe differently should get bullet — seems to be another; and authoritarian loyalty seems to be another still.

We could talk about intolerance in general, rather than "fundamentalism"; but even this raises the difficulty that some people take peaceful disagreement with their beliefs to be a form of "intolerance". There's not a word for this idea that isn't fraught with political conflict.

While this division is nowhere near the extreme in the rationalist communities, I can definitely imagine it becoming so, particularly if technology advances in the ways that many Less Wrongers predict it will.

This is actually an area where I suspect the LW-cluster is much more universalist than most religionists expect secularists to be. The whole concept of "the coherent extrapolated volition of mankind" explicitly takes in all human experience as significant — thus including religious experience. Religious claims don't have to be true in order for religious experience to be significant as an element of human value; after all, Hamlet isn't true either ....

(Mind you, I also think that most secularists are more universalist than religionists expect secularists to be.)

Some Less Wrongers appear to express the viewpoint that the world would be a better and happier place if all of us were to become rationalists, and I think that this is the attitude that I had in mind when I let the phrase "most dangerous fundamentalists" slip out.

Here I wonder if we (by which I mean the LW-cluster) have been failing to communicate what we mean by "rationalist" and "rationality". One iteration of our Litany of Tarski goes as follows:

If there is a God who loves me,
I desire to believe there is a God who loves me.
If there is not a God who loves me,
I desire to believe there is not a God who loves me.
Let me not become attached to beliefs I may not want.

This is a position of profound submission to the universe. When we say "rationalist" here, we primarily don't mean someone who has a commitment to a particular set of beliefs. We mean someone who wants their beliefs to be caused by the facts of the universe, whatever those might turn out to be.

Medieval Catholics (and some contemporary ones) wanted to make the whole world Catholic. Stalinists wanted to make the whole world Stalinist. In either case, I think the world would have turned out a much worse place had either one succeeded. To you, rationalism, empiricism and positivism might seem to exist in a different category, but to me any ideology or thought system that gets universalized will probably turn into More's Utopia or Plato's Republic. And, while interesting for a while, such places hardly seem very habitable in the long term.

One might then ask, what sort of world is most likely to cultivate and promote the kind of diversity you're advocating here?

But, if Less Wrongers are totalizing and dogmatic about making people happy, then why on earth would you want to deconvert people from religion? Religious beliefs, practices, rituals, spiritualities, aesthetics, values, and communities bring vast amounts of happiness to people all over the world, every day. No, it's not for everyone, but why try and take it away from the people who find so much happiness in it?

I, personally, don't spend any particular effort on deconverting anyone. Not much point: anyone who can be deconverted by less than sufficient evidence can probably be reconverted by less than sufficient evidence.

I would like, however, to find ways to offer more comfort to people who have deconverted and lost their religious social support structure, e.g. been rejected by family. That sort of thing strikes me as acutely unfortunate. But then, my own Christian family didn't give me any particularly acute trouble through my migration from Christian to pagan to atheist.

I find some redeeming qualities in Catholicism precisely in the Church as an institution

Can you point to somewhere you've explained this already - or failing that, would you be so kind as to unpack it a little?

I must confess that, as an outsider to (but occasional reader of) Less Wrong, I find certain statements and arguments on this site to be just as totalizing and dogmatic as the most dangerous religious fundamentalism. There's also a fair amount that I find personally offensive to my value system. However, whenever I find myself going into a nasty tirade against LW, my atheist rationalist friend (who introduced me to this site in the first place) urges me to remember that not all Less Wrongers are the same. Opinions about things like the Singularity vary greatly, as do values. And, there are even some theists on this site.

I often see this in discussions or debates on religion. The only use for it is to bring disagreements onto a plane of relativism and thereby removing any possibility of conclusion. "I believe this, and you believe that, but aren't we so similar in many ways? Let's be tolerant of each other and allow for whatever beliefs we like."

So, yes, you can draw parallels, some of them accurate, however you can't soundly claim to have the preponderance of impersonal evidence on your side. We haven't reason to treat your beliefs with respect. You should have reason to respect our beliefs if you respect impersonal evidence.

Now, given the assumption that our beliefs are reasonably accurate, are we really totalizing and dogmatic? Is it totalizing and dogmatic to say "young earth creationists are wrong," even when they have more than enough personal evidence for such beliefs? Even when we sound like them? I think it only appears totalizing and dogmatic if you ignore context--if you draw the argument onto relativistic ground.

* I'm giving away more than I should by allowing for coherency in personal evidence for the proposition of a God as described by X religion. The fact is is that even accounting for personal evidence, such as personal revelation, their beliefs are wrong in the Bayesian sense when accounting for non-personal evidence.

I must confess that, as an outsider to (but occasional reader of) Less Wrong, I find certain statements and arguments on this site to be just as totalizing and dogmatic as the most dangerous religious fundamentalism.

That seems like a surprising claim! I'd like to explore it further.

The most dangerous religious fundamentalisms lead people to do things such as blowing up buildings, committing mass murders, jailing and torturing people for apostasy, and throwing acid in the faces of schoolchildren. This occurs both when dangerous religious fundamentalists occupy positions of formal political power (governments), and when they do not (terrorist groups, militias, abortion-clinic bombers).

(Note, I'm not asserting that religions or fundamentalisms in general promote those sorts of things. You specifically said "the most dangerous religious fundamentalism", and I'm taking that limitation in good faith.)

Somehow, nobody around here seems to be doing those sort of things. Indeed, that sort of behavior seems to be pretty rare in the Traditional Rationality community too — the skeptics movement; the New Atheists; etc.

Is that just because we are totalizing and dogmatic about making people happy instead of about hating and killing them? (I am reminded of a Barry Goldwater quote about extremism and moderation.)

Or do you think there is some other reason?

Jay, I can certainly empathize with your concern for your friend. However, as a practicing Catholic I can assure you that your friend will not be surrounded by people trying to convince her that she needs to "repent" of her sexuality. There's less that I can say about dark side epistemology (since you would probably consider me to be an adherent of it!) but I can assure you that Leah is not going to have piles of nonsensical doctrine shoved down her throat. She will be introduced to many ideas, but ultimately she herself will decide what to accept and what to reject (and I highly doubt that she will accept absolutely everything that the Church teaches - many Catholics don't).

I must confess that, as an outsider to (but occasional reader of) Less Wrong, I find certain statements and arguments on this site to be just as totalizing and dogmatic as the most dangerous religious fundamentalism. There's also a fair amount that I find personally offensive to my value system. However, whenever I find myself going into a nasty tirade against LW, my atheist rationalist friend (who introduced me to this site in the first place) urges me to remember that not all Less Wrongers are the same. Opinions about things like the Singularity vary greatly, as do values. And, there are even some theists on this site.

I can tell you that the same is true about Catholicism. It's a very large organization with many people who interpret their religion in many different ways. Yes, there are many things wrong with the Church as an institution, but people know this and some are trying to reform these flaws (indeed, if Leah does convert, she will be a great one to do this). As for the epistemological side...I don't think that Leah is going to reject scientific truths, if that is what worries you. She might just come to view them in a somewhat different way.

Having read Leah's blog for a while, I know that she will respond very well to any challenge/debate you put forward. However, I would advise against trying to thwart her conversion. Ultimately, she has to make her own decisions. As others have said, listen to her and try your to understand the reasons for her conversion. Also, if you haven't already, get to know a few Catholics. We could be wrong, but that doesn't make us bad people.