• There’s an organization based in London called the Rationalist Association. It was founded in 1885. Historically, it focused on publishing books and articles related to atheism and science, including works by Darwin, Bertrand Russell, J. B. S. Haldane, George Bernard Shaw, H. G. Wells, and Karl Popper.
  • The topics covered overlap with the present-day rationalist movement (centered on Lesswrong). They include religion and atheism, philosophy (especially philosophy of science and ethics), evolution, and psychology.
  • According to Wikipedia, membership of the Rationalist Association peaked in 1959 with more than 5000 members and with Bertrand Russell as President.
  • This post displays some covers of Rationalist Association publications, and links to full-text articles and other resources.
  • Prior to reading this biography, I hadn't heard of these earlier rationalists. So I did some quick and shallow research. I’d be curious to know more about this history. It might be worth adding a note to this LW Wiki entry.

Past covers of the Rationalist Association publications

1896 Cover 

  • This is a journal for short articles called the “Agnostic Annual” (later “Rationalist Annual”). The full text is here.
  • Some quotes from the article “Mind as controlled by matter” below.

1938 Cover

Includes articles by Bertrand Russell and evolutionary biologist and proto-transhumanist J. B. S. Haldane.

1954 Cover

1971 Cover

  • This is for a magazine called The Humanist, published by the Rationalist Association. It has since published articles by Richard Dawkins and Daniel Dennett.
  • Contents: “Rationalist Tasks”, “Motoring Safety”, “Quasi-rational Quarrelling” and the first appearance of the famous Philip Larkin poem that begins “They fuck you up, your mum and dad”.

1. Full-text articles from the Rationalist Annual by the prolific biologist, popular science writer and communist, J. B. S. Haldane. Some titles:

  • Why I am a Materialist
  • The Laws of Nature [probabilistic theories in physics and genetics, Laplace’s Demon]
  • The Limitations of Rationalism [cognitive limitations and biases -- see below]
  • A Rationalist Approach to the Problem of Sexual Relations
  • On Being Finite [reflections on death and meaning in life -- see below]

2. Full-text article by Ernest Gellner “On Being Wrong” [epistemic corrigibility]

3. Wikipedia on the (British) Rationalist Association, the Indian Rationalist Association, and the Rationalist International

4. Archive of the Rationalist Annual and New Humanist (pay-walled). 


Some Random Quotes                       

Yet it seemed to me that we have greater control over the material than the immaterial; it being easier, for instance, to regulate diet than to command success [see Scott Alexander]; and that, this being so, we must learn to call nothing common nor unclean, but consider a careful investigation into the influences of food, medicine, and climate as beneath the notice neither of philosopher nor moralist

‘Of all the great branches of human knowledge, medicine is that in which the accomplished results are most obviously imperfect and provisional. The medicine of inhalation is still in its infancy; and yet it is by inhalation that nature produces most of her diseases, and effects most of her cures’

From “Mind as controlled by matter” by Constance Plumptre (1896)


More serious is my own and other people’s limited reason­ing power. I simply cannot grasp a sufficiently complicated argument. The limitations of different intellects vary. Every educated person can factorize 35 in his or her head. I can factorize such numbers as 11,009; a few people can factorize six-figure numbers, however large their factors, Nobody can factorize twenty-figure numbers with large factors. This kind of thing can be done with a specially designed machine, and machines can already vastly extend the scope of our reasoning power in the field of mathematics. I believe that we are only at the very beginning of the use of mechanical aids to reasoning, and that they will be as important as mechanical supplements to our senses, such as microscopes. But they will only take us a certain distance.

From “The Limitations of Rationalism” by J. B. S. Haldane (1947 -- link)                                               

I have tried morphine, heroin, and bhang and ganja (hemp prepared for eating and smoking). The alterations of my consciousness due to these drugs were trivial compared with those produced in the course of my work [as an evolutionary biologist]. I once dreamed that I was reading a life of Christ written and illustrated by Edward Lear. But I can only re­member Pontius Pilate’s moustache. If you want a dream as original as that, don’t take opium, but eat sixty grams of hexahydrated strontium chloride [not medical advice -- OE]. I have had some of the standard adventurous experiences such as being pulled out of a crevasse in a glacier, and more which are unusual. For ex­ample, I was one of the first two people to pass forty-eight hours in a miniature submarine, and one of the first few to get out of one under water. I doubt whether, given my psychological make-up, I should have found many greater thrills in a hundred lives. So when the angel with the darker drink at last shall find me by the river’s brink, and offering his cup, invite my soul forth to my lips to quaff, I shall not shrink.

From “On Being Finite” by J. B. S. Haldane (1965 -- link)



Past presidents of the Rationalist Association include Bertrand Russell, the founder of the Bletchley Park estate, the co-founder of the London School of Economics, and my dad’s ex-father-in-law.

Here’s an effusive advert for a book on “The Science of Life” by H. G. Wells, Julian Huxley and G. P. Wells:


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As a data-point, I'm a rationalist, and a subscriber to the New Humanist, which is published by the Rationalist Association you mention, and is the descendant of the 1971 magazine you mention titled 'The Humanist'.

So I fall into the intersection of LW rationalists and "1950's rationalists".


The New Humanist has been in print for 131 years; starting out life as Watts's Literary Guide, founded by C. A. Watts in November 1885.[4] It later became The Literary Guide and Rationalist Review (1894–1954), Humanist (1956–1971) and the New Humanist in 1972.

Thanks! I appreciate knowing this. Do you happen to know if there's a connection between these 1950's rationalists, and the "critical rationalists" (who are a contemporary movement that involves David Deutsch, the "taking children seriously" people, and some larger set of folks who try to practice a certain set of motions and are based out of the UK, I think)?

the “critical rationalists” (who are a contemporary movement that involves David Deutsch, the “taking children seriously” people, and some larger set of folks who try to practice a certain set of motions and are based out of the UK, I think)?

Critical rationalism is basically the scientific philosophy of Karl R. Popper. An Austrian, he relocated to the UK in the 30s for similar reasons to Sigmund Freud's. So CR ended as being a kind of UK thing, despite having its roots in the Vienna Circle. (It also has a following in Oz and NZ, but not so much in the states).

It's not particularly contemporary, therefore...more of a version 2.0 of logical positivism. I don't know of any specific connection between mid 20th century UK atheism/humanism and CR...but it would be strange if there were none.

There were a lot of developments in philosophy-of-science post WWII -- Kuhn, Feyerabend , etc -- and CR somewhat faded from fashion until Deutsch revived it with his popular work in the 1990s. (Although Popper's falsificational criterion for science remains popular among working scientists).

Deutsch's (and other subsequent) versions of CR got entangled with Austrian economic, libertarianism ,and various other minority beliefs.

I think the link in your comment points to something that seems like a one-man show. The man's name is Elliot Temple.

He has a picture on his homepage about the philosophical traditions he builds on, and apparently he makes some money selling his wisdom, but is he actually a part of some larger debate? I mean, other than the forum he owns and writes most of the comments on, with only two or three other active participants.

By the way, he was posting on LW, and got banned. He accuses David Deutch of organizing harassment against him, and generally seems obsessed about him. Generally, he seems... well, crazy... in a way that is not immediately obvious, but once you start talking to him and get his attention, you are probably going to regret it, because he just can't stop. He will write a ton of text, a separate essay analyzing the meaning and logical flaws of every single sentence you wrote, then he will accuse you of being irrational, and then he will accuse you of being irrational for not responding to him in the same way, and then he will keep writing articles on his blog about how irrational and cowardly you are for avoiding him.

Nice, thanks for sharing.

I was just thinking how "rationalist" has been an increasingly positive-associated label that we can be proud to self-identify as, and it's currently serving as a useful positive signal when others apply it to themselves (for me at least).

The LW community and related rationalist clusters have been doing influential work in various fields: AI and AI safety, the theory and practice of science, journalism, effective altruism, entrepreneurship, investing, pedagogical fanfiction, and more. As a result, the term "rationalist" has been building momentum, and I expect we'll increasingly see high-performers associating with it in various domains, the way "evidence-based" has gotten to the point of sounding good in every domain.

I've also noticed that using the longer label "aspiring rationalist" is less common these days, and I'm glad we're just settling on "rationalist", since anyway rationalists are many things besides epistemically humble and goal-oriented.

Something I think I picked up from LW is that there were historical groups called the rationalists and empiricists, where the empiricists were all about doing experiements and looking at the world, and the rationalists were all about figuring things out just by thinking.

Are these rationalists the same ones as those, and is that a fair description of them? (Or if not fair, is it sort of uncharitable-but-kinda-true?)

This distinction was always fake. The Wikipedia page on Rationalism begins with portraits of Descartes, Spinoza, and Leibniz. Spinoza was a lens grinder who worked closely with astronomer-physicist Christiaan Huygens and wrote in his magnum opus, Ethics, that we only know about things in the world through our bodies interacting with them. It is unclear to me how it is possible for someone to be more committed to looking at the world.  The Wikipedia page on Empiricism begins with portraits of Francis Bacon, John Locke, and David Hume. Hume's An Enquiry Concerning Human Understanding includes the following, which implies that abstract mathematical reasoning is one of the two valid sources of knowledge, and refers to experimental reasoning:

If we take in our hand any volume; of divinity or school metaphysics, for instance; let us ask, Does it contain any abstract reasoning concerning quantity or number? No. Does it contain any experimental reasoning concerning matter of fact and existence? No. Commit it then to the flames: for it can contain nothing but sophistry and illusion.

That quote is metal as hell <3

It might not be actually true, or actually good advice... but it is metal as hell :-)

No, 'rational' here is being used in opposition to 'irrational', 'religious', 'superstitious', etc., not in opposition to 'empirical'.

Quoting Wikipedia:

In politics, rationalism, since the Enlightenment, historically emphasized a "politics of reason" centered upon rational choice, deontology, utilitarianism, secularism, and irreligion[23] – the latter aspect's antitheism was later softened by the adoption of pluralistic reasoning methods practicable regardless of religious or irreligious ideology.[24][25] In this regard, the philosopher John Cottingham[26] noted how rationalism, a methodology, became socially conflated with atheism, a worldview:

"In the past, particularly in the 17th and 18th centuries, the term 'rationalist' was often used to refer to free thinkers of an anti-clerical and anti-religious outlook, and for a time the word acquired a distinctly pejorative force (thus in 1670 Sanderson spoke disparagingly of 'a mere rationalist, that is to say in plain English an atheist of the late edition...'). The use of the label 'rationalist' to characterize a world outlook which has no place for the supernatural is becoming less popular today; terms like 'humanist' or 'materialist' seem largely to have taken its place. But the old usage still survives."

The Online Etymology Dictionary says:

1620s, "one who follows reason and not authority in thought or speculation," especially "physician whose treatment is based on reasoning," from rational + -ist. In theology/philosophy, "one who applies rational criticism to the claims of supernatural authority or revelation," 1640s. This sense shades into that of "one who believes that human reason, properly employed, renders religion superfluous." Related: Rationalistic; rationalism (1800 in medicine; 1827 in theology, "adherence to the supremacy of reason in matters of belief or conduct;" by 1876 in general use).

Separately, your definitions for rationalist vs. empiricist are off. Per SEP, the usual definition is some variant of 'rationalists think we have some innate knowledge, while empiricists think we get all our knowledge from experience'.

Alberto Vanzo argues that the modern philosophical 'rationalist vs. empiricist' dichotomy comes from Kant and early Kant-influenced thinkers. Though the dichotomies 'rational vs. irrational' and 'reason vs. experience' are both much older than the term 'rationalist'; e.g., Francis Bacon in ~1600 was contrasting 'rationalis' with 'empiricus', though this was talking about dogmatists vs. experimentalists, not talking about the modern (Kant-inspired) rationalist v. empiricist dichotomy.

Thanks, Rob! I agree with this summary. It is unfortunate that "rationalism" has this standard usage in philosophy ("rationalist vs empiricist"). This usage is not completely unrelated to the "rational vs superstitious/irrational" distinction, which makes it more likely to confuse. That said, outside of the fields of philosophy and intellectual history, not many people are aware of the rationalist/empiricist distinction, and so I don't see it as a major problem. 

If I try to steelman the Rationalist-Empiricist divide:

Empiricists think that arguments justifying organized violence are nonsense so we ought to ignore them, do what we like instead, and argue about math and science.

Rationalists think that arguments justifying organized violence are sketchy so we should investigate them carefully as hypotheses for how mind organizes itself in the world.

That poem was amazing.

How does a person factorize 11,009 in their head?

Basically you do long division by every prime less than 100. 

I don't understand, its factors are 101 and 109, both are more than 100.

Well, you check if it's a multiple of every prime below sqrt(11009) ~= 105.

Though if you suspect he's intentionally chosen a tricky number, a product of two large primes, you can look at the square numbers larger than 11009. In this case 11025 = 105^2, and 11025-11009 = 16 = 4^2, so 11009 = 105^2 - 4^2 = (105+4)(105-4) = 109×101

That's funny. "100" was a stand-in for sqrt(11009), I didn't anticipate that all factors would actually be above 100. 

Curated. I really like seeing this, seeing how LessWrong's intellectual tradition is part of larger rational tradition and culture. There's a certain fun to it.

There is also a French non-profit called the Rationalist Union, co-founded by Langevin (of the Langevin Equation and Twin Paradox). Apparently, Borel, Einstein, and Hadamard all had some honorary role in the past. Like the British Rationalist Association, it seems it was associated with socialism and communism during the mid-20th Century. The best source I could find is translated French Wikipedia. 

Yeah. The communist associations of past iterations of "rationalist" schools or communities is one the biggest piles of skulls I know about and try to always keep in mind.

Wikipedia uses this URL about Stalin, Wells, Shaw, and the holodomor as a citation to argue that, in fact, many of them were either duped fools or worse into denying the holodomor. Quoting from the source there:

Shaw had met Stalin in the Kremlin on 29 July 1931, and the Soviet leader had facilitated his tour of Russia in which he was able to observe, at least to his own satisfaction, that the statements being circulated about the famine in the Ukraine were merely rumours. He had seen that the peasants had plenty of food. In fact the famine had notoriously been caused by Stalin in his desperation to achieve the goals of his five-year plan. An estimated ten million people, mostly Ukrainians, died of starvation.

As someone who flirts with identifying as part of some kind of "rationalist" community, I find the actions of Shaw to be complicatedly troubling, and to disrupt "easy clean identification".

Either I feel I must disavow Shaw, people like Shaw, and their gross and terrible political errors that related to some of the biggest issues and tragedies of their era, or else I must say that Shaw is still a sort of somehow a tolerably acceptable human to imagine collaborating with in limited ways in spite of his manifest flaws. 

(From within judeo-christian philosophic frames this doesn't seem super hard. The story is simply that all humans are quite bad by default, and it is rare and lucky for us to rise above our normal brokenness, and so any big non-monstrous actions a human performs is nearly pure bonus, and worthy of at least some praise no matter what other bad things are co-occuring in the soul of any given person.)

Shaw's kind of error also troubles me when I imagine that there might be some deep substructure to reasoning and philosophy such that he and I share a philosophy somehow, and he did that while having a philosophy like mine... then if "beliefs cause behavior" (rather than mostly just being confabulated rationalizations after behaviors have already occured) then I find myself somewhat worried about the foundations of my own philosophy, and what horrible things it might cause me to "accidentally" endorse or promote through my own actions.

Maybe there is some way to use Shaw's failure as a test case, and somehow trace the causality of his thinking to his bad actions, and then find any analogous flaws in myself and perform cautious self modification until analogous flaws are unlikely to exist?  But that seems like a BIG project. I'm not sure my life is long enough to learn all the necessary facts and reasoning carefully enough to carry a project like that to adequate completion.

Thus the practical upshot, for me, is to be open to "fearing to tread" even more than normal until or unless there are pretty subjectively clear reasons to advance.

Also, my acknowledged limitations lead me to feel a minor duty to sometimes point out obviously evil things that my mental stance can't help but see as pretty darn evil? Not all of them. Just really really big and important and obvious ones.

My current working test case for this is the FDA, which I suspect should be legislatively gutted

Maybe I'm wrong? Maybe in saying "FDA delenda est" semi-regularly I'm making a "Shaw and the Holodomor level error" by doing the opposite of what is good? 

It seems virtuous, then, to at least emit such an idea every so often, when I actually really can't help but believe in and directly see a certain evil, and see if anyone can offer coherent disagreement or agreement and thereby either (1) help fix the world by reducing that particular evil or else (2) help me get a better calibrated moral compass.  Either way it seems like it would be good?

Also, in general, I feel that it is a good practice to, minimally, acknowledge the skulls so that I know that "ideas and identities and tendencies similar to mine" might have, in the past, lead to bad places.

To hide or flinch from the fact that former-"people calling themselves rationalists" were sometimes pretty bad at the biggest questions of suffering and happiness, or good and evil, seems like... like... probably not what someone who was good at virtue epistemology would do?  So, I probably shouldn't flinch. Probably.

I'm interested to know how much the prominent figures in these past Rationalist groups cared about rationality itself rather than its bedfellows (science, atheism, socialism or communism etc.). A related question is whether these groups sometimes functioned as a fig leaf for a certain kind of political association (e.g. scientifically-minded socialists).  

 From reading the J. B. S. Haldane biography linked in the OP, I got the sense that Haldane cared most about science and the status of scientists in society. He seems to care less about rationality per se than science. He was a devoted communist for a period but this also stems (in part) from the value he places on science. (He had the view that communist countries gave more status to scientists and were run more scientifically.) So I doubt he was involved with the Rationalist Association because of the politics (though maybe if the politics were very conservative he would have left).


Your concern makes a lot of sense. From my perspective, the lesson is "wannabe rationalists easily get politically mindkilled". Whether you are woke, or alt-right, or libertarian, political allegiance always pushes you towards denying some politically inconvenient parts of reality.

(Different parts of reality are inconvenient for different political tribes; so you can still ignore one part of reality and feel intellectually superior to those differently politically mindkilled people who ignore a different part of reality. I suppose this is how Shaw felt.)

Or more generally, contrarians are also gullible as fuck, only about different things than the majority.

For example, my sympathies are roughly on the libertarian side, but I obviously notice it is often libertarians talking nonsense on topics like global warming or covid. Because those are exactly the parts of reality that are inconvenient for libertarians: where an isolated individual effort achieves practically nothing, and a collective action is needed to solve the problem. How inconvenient!

(And similarly, it is inconvenient for a socialist when Soviet Union... or Venezuela turns out to be a disaster. Oh wait, this is not true socialism, because nothing ever is. Similarly, North Korea is inconvenient for a neoreactionary; but don't worry, North Korea is not a true family-owned state, because nothing ever is. Heredity of traits is inconvenient for the woke. Evolution is inconvenient for the religious. Etc.)

Maybe in saying "FDA delenda est" semi-regularly I'm making a "Shaw and the Holodomor level error" by doing the opposite of what is good?

Yes, it is possible. But I believe there is a middle ground where FDA is not destroyed completely, only the rules are changed, so that something not being approved by FDA (yet) is not a complete obstacle, or perhaps there are different levels of "approval" and some of them are granted rather quickly.

But whatever you do (whether you call yourself a rationalist or not), you should keep looking at the reality, evaluating new data, and sometimes changing your opinion.

It might also have been the case that a tour of Russia organized by Stalin indeed showed Shaw a bunch of towns that got extra food delieveries right before Shaw entered the town. Shaw then neither spoke Ukranian nor Russian and was likely dependend on a Soviet translator to talk with the peasants.

His problem might have been that he believed the evidence that Stalin carefully selected for him to be representative of the situation. 

The holodomor denialism seems very similar to lab leak denailism. Lab leak denailism is also about trusting in certain authorities because you agree with them in your philosophical worldview and then accepting their cherry-picked and manipulated evidence.

With Omicron potentially escaping from South African labs, the lab leak denailism might even be more deadly. Avoiding holodomor denialism in the West wouldn't have prevented or ended it. On the the other hand getting rid of lab leak denialism would have increased biosafety protocols. 

The topics covered overlap with the present-day rationalist movement (centered on Lesswrong). They include religion and atheism, philosophy (especially philosophy of science and ethics), evolution, and psychology.

Religion and atheism isn't a central topic of LessWrong. To the extend that religion is a topic, it's more "what can we learn from religion" then about opposing it. At least I don't remember any highly received new atheist writing in the last years on LessWrong.

As far as evolution goes shows few recent writing about it.

At the beginning, LessWrong was strongly atheistic:

Later, writing about religion felt like beating a dead horse.

Then, I suppose as a part of the "meta-rationality" wave, the idea of cultural evolution became popular: how people can do the right things for wrong reasons (and premature rationality can hurt you), for example how divination is useful, not because supernatural things are actually true, but because divination is effectively a source of randomness, so it is useful where a random-number generator would be useful, e.g. when fighting an intelligent adversary or hunting animals. This made religion somewhat acceptable -- perhaps not epistemically, but instrumentally.

We also had the period when LessWrong was effectively dead and replaced by Slate Star Codex as a center of rationalist discource, but SSC was not explicitly atheist, and at least half of its comment section did not even aspire to be rationalist.

Lately Buddhism became popular on LessWrong -- a fact that I hate, and I have already complained about it many times -- first it started as "there seems to be some scientific evidence in favor of meditation giving its users some benefits" which is okay if true, but of course the entire expert literature on this topic is full of memetic hazards, and we gradually move towards accepting parts of Buddhist epistemology, or at least privileging them as hypotheses. (Sometimes I imagine a parallel universe where e.g. Catholics have invented push-ups, and the rationalists in that universe progress from "hey, there is a scientific evidence that push-ups are good for your body" towards accepting the wisdom of Catholicism and praying to Lord Jesus.) I sincerely hope that this all is just temporary and we will grow out of it, better sooner than later.

(And I suspect the recent silence on the topic also reflects the recent changes in American politics. To put it bluntly, a decade or more ago, it was like "religion = Republicans = the bad guys", but then people realized that Islam is a religion too, and being a too consistent atheist also makes you "islamophobic", which is a politically incorrect thing, and therefore it is better to just avoid this topic.)

This is a great list of posts. I had some of these in mind but hadn't remembered all of these. Thanks!

Early LessWrong was atheist, but everything on the internet around the time LW was taking off had a position in that debate. "...the defining feature of this period wasn’t just that there were a lot of atheism-focused things. It was how the religious-vs-atheist conflict subtly bled into everything." Or less subtly, in this case. 

I see it just as a product of the times. I certainly found the anti-theist content in Rationality: A to Z to be slightly jarring on a re-read -- on other topics, Elizer is careful to not bring into it the political issues of the day that could emotionally overshadown the more subtle points he's making about thought in general -- but he'll drop in extremely anti religion jabs despite that. To me, that's just part of reading history. 

Yes, I said "overlap" not "coincide" for that reason. The present movement has more discussion of applied epistemology, ideology, and world-view formation, and less discussion specifically focused on religion. My sense is that the earlier movement is also more focused on Christianity than on religion or ideology in general. 

Evolution was a pretty new theory in 1880 and so it makes sense it would be discussed more. (AI is a big topic for the present movement and not for the earlier). 

I can only agree , since I've been saying for a long time that the current rationalist movement is only the latest iteration of many.

(Also the reference to The Science of Life reminded of my grandfather on my father's side , who was a great believer in self education and owned a number of Welles's non fiction works including that one).