A brouhaha has erupted between Tyler Cowen and the Rationality community over comments made in an interview with Ezra Klein, in in which Tyler Cowen, in an uncharacteristic outburst of candidness, lambasted the Rationality community for what he perceives as religiosity and homogeneity:
But I would approve of them much more if they called themselves the irrationality community. Because it is just another kind of religion. A different set of ethoses. And there’s nothing wrong with that, but the notion that this is, like, the true, objective vantage point I find highly objectionable. And that pops up in some of those people more than others. But I think it needs to be realized it’s an extremely culturally specific way of viewing the world, and that’s one of the main things travel can teach you.
Bryan Caplan offered an opposite take, but still criticizes what he perceives as rationalism being too deferential to utilitarianism.
The rationality community is one of the brightest lights in the modern intellectual firmament. Its fundamentals – applied Bayesianism and hyper-awareness of psychological bias – provide the one true, objective vantage point. It’s not “just another kind of religion”; it’s a self-conscious effort to root out the epistemic corruption that religion exemplifies (though hardly monopolizes). On average, these methods pay off: The rationality community’s views are more likely to be true than any other community I know of.
Both blog posts generated significant discussion, spilling over to Reddit and Twitter as well, with Will Wilkinson tweeting out a 14-tweet ‘tweet storm’ criticizing the Rationality community. As with many internet feuds, the intensity is inversely proportional to the stakes. Tyler’s interview was a disappointment and reeked of ‘virtue signaling’ (the line: extremely culturally specific way of viewing the world).
Rationalism is a religion
A major criticism is that Rationality community behaves like a religion, but coated in a veneer of science and reason…But if you go through the comments of Rationalist communities and blogs, the fact Rationalists are so open to being wrong about rationalism, is part of rationalism. Straw-manning is frowned upon, in favor of ‘steel manning’, almost to a fault.  It’s the opposite of group-think. Rationalism is provisional, meaning it’s open to amendment. For example, if alien life were found, for ‘young earth’ creationists it would mean that they would have to rationalize how the Bible is still correct (maybe the aliens are fake or are a conspiracy…I dunno). Scientists, however, would modify the theory of evolution: first, by discarding the hypothesis that all life is earth-based. Science is provisional; religious orthodoxy is not. 
Rationalism in the context of Slate Star Codex (and the rest of the Rationalist community) is based heavily on empiricism (such as behavior studies, drug studies, and psychology), and to some extent, Platonic realism (such as mathematical concepts), but religion involves rationalism in the philosophical sense (meaning it’s purely mental). In terms of ontology, religion is idealist; Rationalism is materialistic.
Rationalists place precedence on the scientific method, eschewing superstition and intuition. Rationalism is very evidence-based. I can’t just proclaim ‘AI will always be friendly’ and expect people to nod along– I would need to provide evidence–such as in the form of some sort of empirical test or a mathematical construct–that it is. But perhaps Eliezer Yudkowsky’s views on AI (such a his insistence of ‘friendly AI’) may come across as too dogmatic, and the Rationality community doesn’t do enough to challenge the views of its more established members.
Rationalism is too Spock-like
Although some liken Rationalism to a religion, others argue it’s too enamored with science and ‘reason’. Critics sometimes draw parallels between Rationalists and Spock (who embodies ‘pure reason’)…But consider evolution…virtually all Rationalists believe it, but evolutionary biology is the possibly the most empirical of all fields…it’s literally digging up stuff and putting it under a microscope. That doesn’t seem very Spock-like. Spock would already know based on pure reason alone, without having to resort to all that dirty work. Evolutionary and cognitive scientists Dawkins, Harris, Dennett, and even Gregory Cochran are held in high regard by the Rationality community.
The same goes for drug studies(pharmacology), behavior science, and psychology, all valued by the Rationality community and all empirical.
Overemphasis on ‘reason’; Hume’s guillotine; hubris; limitations of science and knowledge
6. Hume is right. Good things, like reason, come from co-opting and reshaping base motives. Reason’s enslaved to the impulse that drives it.
12. The inclination to choose epistemic rationality is evidence of being bad at life.
Hume was an empiricist…the Rationalist community largely is empiricist and Platonic. Based on those two criteria, Wilkinson (being an empirically minded Platonic realist himself) would agree with the ethos of the Rationality community, but he’s making an erroneous judgement based on the nomenclature ‘Rationalist’ alone.
As mentioned above, Rationalists are open to being wrong, and don’t claim a monopoly on ‘reason’; second, Rationalism is also an epistemological approach, not only an ontological one, which means anyone, regardless of their politics, can apply it. It’s like a tool in a toolbox.
But in trying to see the other side of the argument, the problem I suspect is that Rationalists are too confident (or are perceived as being too confident) about the ability of science to answer questions pertaining to existence and morality, which ties into ontology, and idealism vs. materialism (and related positivism and scientism). Some argue there will always be phenomenon that cannot be explained by science, and that science represents an incomplete picture of reality (many scientists also believe this. It doesn’t mean (as some atheists wrongly assume) a rejection of science, but rather acknowledging the limitations of science). Science is descriptive, but possible problems arise when it becomes prescriptive. That’s where the whole is/ought thing comes into play (echoing Caplan’s critique). Some people are uncomfortable with the idea of using science to solve social and moral problems, because science ignores or overlooks things that cannot be quantified in a scientific sense. For example, the ethics of euthanasia and ending life support. Is there consciousness that cannot be measured by scientific means? This is related to the mind-body problem.
From the post: The Healthcare Debate: Confronting Reality:
Going back to the idealism v. materialism post, a materialist may argue that consciousness and being are entirely physical (eliminative materialism), without spirit or a soul–hence a quantifiable, material value (economic or scientific) can be ascribed to individual life, justifying euthanasia and organ transplantation, as consciousness is inseparable from the brain, so if the brain empirically appears dead (diminished or absence of brain activity in response to stimuli), so too is consciousness and the body. This is the opposite view as espoused by dualism. An idealist, on the other hand, is not convinced, arguing that there are aspects of ‘being’ that are not physical (ontological argument). Epistemologically, an idealist may argue that there are imitations to what what we can know about consciousness or the value of human life, that can’t be measured by a machine or economic value (limitations of knowledge). In his mind, the idealist rationalizes that the patient has some form of sentience despite the empirical evidence showing otherwise.
Regarding consequentialism, as a minarchist consequentialist myself, consequentialism (and related utilitarianism ) is an inescapable part of any developed society. You cannot always derive an ought from an is, but sometimes you can. (I will expand my critique of Caplan’s criticism of utilitarianism later.)
Another criticism is Rationalism puts much faith in inductive reasoning, which has various biases such as the availability bias. Taleb frequently cites the ‘turkey problem’. I don’t agree with Taleb, but it’s a common criticism.
My take is, inductive reasoning is the best we have of all the alternatives. Taleb’s reasoning is fallacious ( argumentum ad ignorantiam) because it requires the other side to prove a negative (that there won’t be a black swan, which is impossible to do). The inability to find such a proof doesn’t make Taleb right. Like saying the inability to disprove that UFOs exist proves there are UFOs.
Scientists and Rationalists seldom think in absolutes, as Taleb incorrectly assumes. Instead of a scientist proclaiming that “because we only observe white swans, all swans are white,” rather he would say (or imply) “we believe based on the preponderance of evidence, swans are white, but this is always subject to change pending new evidence.”
Neoclassical economics, which includes the efficient market hypothesis , does an adequate job of describing reality and things that have already happened, is so-so at dictating policy (fed policy was a success, but Obama’s Keynesian-inspired stimulus wasn’t ), but is less adept at predicting. I think many economists and people in finance are well-aware of the limitations off their models, whereas Taleb and others create strawmen that such economists are totally clueless. As I explain in the post Why Economists Don’t Need to Be Able to Predict, doctors can’t predict if or when someone will can cancer, but they can offer a treatment and an explanation for the processes that causes cancer, yet doctors play an invaluable role in society. In the past, medicine was iatrogenic, but great advances have been made to treating disease and prolonging life, which is an example of science succeeding.
Rationalism is clannish
Another criticism is supposed clannishness. Rationalism, being that it’s both a community and epistemology, some ‘identity’ is involved . The in-group being themselves and the out-group those who don’t agree with Rationalists’ epistemological and ontological approach, but Rationalists are pretty charitable to the out-group (and hard on each other too ).
Overall, the Rationality community isn’t really a ‘movement’…Like NRx, it’s not trying to win a popularity contest, where things like PR matter and ‘mass appeal’ matter. Rationalism should be kinda esoteric and ‘nerdy’; otherwise, it risks become like any other ‘boring’, low-information political forum where the same predictable stuff is repeated over and over.
 There was a post awhile back that went hugely viral The Other Side is Not Dumb. Rationalists resist the temptation to create and fall for seductive, intellectually lazy reductionist narratives that pigeonhole the ‘other side’. Augments that seem obvious to ‘us’ have almost certainty been addressed by the ‘other side’, and reusing these well-worn narratives as if they are somehow revelatory and profound, when they aren’t, is an insult to the intelligence of both sides. A greater understanding of one’s ‘own’ side is attained by ‘Steel manning’ the opposing side, in ascribing the most charitable view of your opponent.
 This is how science is supposed to work in theory; of course, it’s not away perfect, and sometimes unpopular ideas (such as skepticism of anthropogenic global warming) are met with hostility or ignored by the scientific community. Scott remarked that everything is a religion…maybe there is some truth to that.
 Intellectual movements (online at least, I cannot speak for the offline world) tend to reject absolutist/binary thinking and ‘weak man’ arguments, and are quite hard on each other (there is perhaps a tendency for Rationalists to be too charitable to opposing views, although the EY ‘worship’ may be an exception to this). You see this nitpicking on the intellectual far-right too. On NRx and alt-right blogs, it’s not uncommon for there to be strong disagreement between members on more subtle issues even though they all agree ‘liberalism is bad’.
For example, I were to post an article /r/the_donald “5 reason why Donald Trump is the best president ever” or on /r/sanders “5 reason why Bernie Sanders deserved to win,” both articles would get a lot of up-votes and comments in agreement. But an article “5 reason why Rationalism is the best epistemology ever,” Rationalists would try to punch holes in it to try to prove that it isn’t, because for smart people correctness is more important than identity and consensus, which ties into ‘intellectualism culture’. Pandering and preaching to the choir is perceived as low-information. Intellectuals seek challenge; they want their views to be challenged, which goes against prevailing thought and intuition that affirmations, not disagreement, are more valued. In other words, low-information groups want their biases confirmed; high-IQ people want them challenged. This may be why Rationalists may seem so deferential to the out-group and why they are often their own harshest critics.
 The poor performance of active management and individual stock traders lends support to the EMH. But how efficient is it? That is harder to attain, but I suspect mostly so, with tiny inefficiencies that are limited by ‘size effects’. The stock market involves incomplete information, meaning no one can be certain about anything (such as whether a company is overvalued, a fraud, etc.) until after the fact, although there are heuristics one can use to try make such an assessment. Economically, to ‘be rational’ is to choose a choice that yields the highest expected value, of all available choices. But because the information is incomplete or asymmetrical, the most feasible option is what I call ‘real time‘ rationalism, which is based on empiricism and inductive reasoning. One cannot make a purely rational (in terms of epistemology) choice if information is incomplete. Smart people know that the lottery has a negative expected value (the lottery is complete, and the odds are known), so they can rationalize (via pure reason) not to play; the less intelligent cannot rationalize this, so they buy tickets upon seeing the empirical evidence of some people winning and getting a lot of media attention.
 I’ll just split the difference: the left and right were wrong on many things. The stimulus didn’t do anything and there was no hyperinflation/dollar collapse. Bernanke is the only one who got it right.