(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.