> non-rationalists do at least benefit from some intellectual humility

The Islamists who took out the World Trade Center don’t strike me as particularly intellectually humble.

If you reject reason, you are only left with force.

Are you so sure the 9/11 hijackers rejected reason?

Why Are So Many Terrorists Engineers?

https://archive.is/XA4zb

Self-described rationalists can and often do rationalize acts and beliefs that seem baldly irrational to others.

I now feel the need to comment that this thread does illustrate an issue I have with the naming of the philosophical/internet community of rationalism.

One can very clearly be a rational individual or an individual who practices reason and not associate with the internet community of rationalism. The median member of the group defined as "not being part of the internet-organized movement of rationalism and not reading lesswrong posts" is not "religious extremist striking the world trade center and committing an atrocious act of terrorism", it's "random person on the street."

And to preempt a specific response some may make to this, yes, the thread here is talking about rationalism as discussed in the blog post above as organized around Yudowsky or slate star codex, and not the rationalist movement of like, Spinoza and company. Very different things philosophically.

Islamic fundamentalism and cult rationalism are both involved in a “total commitment”, “all or nothing” type of thinking. The former is totally committed to a particular literal reading of scripture, the latter, to logical deduction from a set of chosen premises. Both modes of thinking have produced violent outcomes in the past.

Skepticism, in which no premise or truth claim is regarded as above dispute (or, that it is always permissible and even praiseworthy to suspend one’s judgment on a matter), is the better comparison with rationalism-fundamentalism. It is interesting that skepticism today is often associated with agnostic or atheist religious beliefs, but I consider many religious thinkers in history to have been skeptics par excellence when judged by the standard of their own time. E.g. William Ockham (of Ockham’s razor) was a 14C Franciscan friar (and a fascinating figure) who denied papal infallibility. I count Martin Luther as belonging to the history of skepticism as well, for example, as well as much of the humanist movement that returned to the original Greek sources for the Bible, from the Latin Vulgate translation by Jerome.

The history of ideas is fun to read about. I am hardly an expert, but you may be interested by the history of Aristotelian rationalism, which gained prominence in the medieval west largely through the works of Averroes, a 12C Muslim philosopher who heavily favored Aristotle. In 13C, Thomas Aquinus wrote a definitive Catholic systematic theology, rejecting Averroes but embracing Aristotle. To this day, Catholic theology is still essentially Aristotelian.