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We mean: Epistemic rationality: believing, and updating on evidence, so as to systematically improve the correspondence between your map and the territory. The art of obtaining beliefs that correspond to reality as closely as possible. This correspondence is commonly termed "truth" or "accuracy", and we're happy to call it that.
A popular belief about "rationality" is that rationality opposes all emotion-that all our sadness and all our joy are automatically anti-logical by virtue of be
Some of the comments in this blog have touched on the question of why we ought to seek truth. (Thankfully not many have questioned what truth is.) Our shaping
(Continued from previous post: "Why truth? And...") A bias is a certain kind of obstacle to our goal of obtaining truth - its character as an "obstacle" stems from this goal of truth - but there are many obstacles that are not "biases".
The availability heuristic is judging the frequency or probability of an event, by the ease with which examples of the event come to mind. A famous 1978 study by Lichtenstein, Slovic, Fischhoff, Layman, and Combs, "Judged Frequency of Lethal Events", studied errors in quantifying the severity of risks, or judging which of two dangers occurred more frequently.
Followup to: Conjunction Fallacy "Merely corroborative detail, intended to give artistic verisimilitude to an otherwise bald and unconvincing narrative..."
The Denver International Airport opened 16 months late, at a cost overrun of $2 billion (I've also seen $3.1 billion asserted). The Eurofighter Typhoon, a join
In hindsight bias, people who know the outcome of a situation believe the outcome should have been easy to predict in advance. Knowing the outcome, we reinterp
Homo sapiens' environment of evolutionary adaptedness (aka EEA or "ancestral environment") consisted of hunter-gatherer bands of at most 200 people, with no wri
Continuation of: What is Evidence? Light leaves the Sun and strikes your shoelaces and bounces off; some photons enter the pupils of your eyes and strike your
Thus begins the ancient parable: If a tree falls in a forest and no one hears it, does it make a sound? One says, "Yes it does, for it makes vibrations in the a
In the time of the Roman Empire, civic life was divided between the Blue and Green factions. The Blues and the Greens murdered each other in single combats, in
Followup to: Making Beliefs Pay Rent (in Anticipated Experiences) Carl Sagan once told a parable of a man who comes to us and claims: "There is a dragon in my g
You can have some fun with people whose anticipations get out of sync with what they believe they believe. I was once at a dinner party, trying to explain to a
Followup to: Against Maturity "The hottest place in Hell is reserved for those who in time of crisis remain neutral." -- Dante Alighieri, famous hell ex
The earliest account I know of a scientific experiment is, ironically, the story of Elijah and the priests of Baal. The people of Israel are wavering between Jehovah and Baal, so Elijah announces that he will conduct an experiment to settle it - quite a novel concept in those days!
I once attended a panel on the topic, "Are science and religion compatible?" One of the women on the panel, a pagan, held forth interminably upon how she believ
I have so far distinguished between belief as anticipation-controller, belief in belief, professing and cheering. Of these, we might call anticipation-controll
Followup to: Semantic Stopsigns, We Don't Really Want Your Participation At the Singularity Summit 2007, one of the speakers called for democratic, multination
Will bond yields go up, or down, or remain the same? If you're a TV pundit and your job is to explain the outcome after the fact, then there's no reason to worry. No matter which of the three possibilities comes true, you'll be able to explain why the outcome perfectly fits your pet market theory .
"The sentence 'snow is white' is true if and only if snow is white." -Alfred Tarski"To say of what is, that it is, or of what is not, that it is not, i
Suppose that your good friend, the police commissioner, tells you in strictest confidence that the crime kingpin of your city is Wulky Wilkinsen. As a rationalist, are you licensed to believe this statement? Put it this way: if you go ahead and mess around with Wulky's teenage daughter, I'd call you foolhardy.
Followup to: What is Evidence? Previously, I defined evidence as "an event entangled, by links of cause and effect, with whatever you want to know about", and
Prerequisite: How Much Evidence Does It Take? In 1919, Sir Arthur Eddington led expeditions to Brazil and to the island of Principe, aiming to observe solar e
Followup to: Burdensome Details, How Much Evidence? The more complex an explanation is, the more evidence you need just to find it in belief-space. (In Tradit
(The following happened to me in an IRC chatroom, long enough ago that I was still hanging around in IRC chatrooms. Time has fuzzed the memory and my report ma
From Robyn Dawes's Rational Choice in an Uncertain World: Post-hoc fitting of evidence to hypothesis was involved in a most grievous chapter in United States h
Followup to: Absence of Evidence Is Evidence of Absence. Friedrich Spee von Langenfeld, a priest who heard the confessions of condemned witches, wrote in 1631
This excerpt from Meyers's Exploring Social Psychology is worth reading in entirety. Cullen Murphy, editor of The Atlantic, said that the social sciences turn
Once upon a time, there was an instructor who taught physics students. One day she called them into her class, and showed them a wide, square plate of metal, n
Followup to: Fake Explanations When I was young, I read popular physics books such as Richard Feynman's QED: The Strange Theory of Light and Matter. I knew th
Prerequisites: Fake Explanations, Belief As Attire The preview for the X-Men movie has a voice-over saying: "In every human being... there is the genetic code
Followup to: Fake Explanations, Guessing the Teacher's Password Phlogiston was the 18 century's answer to the Elemental Fire of the Greek alchemists. Ignite w
And the child asked: Q: Where did this rock come from?A: I chipped it off the big boulder, at the center of the village.Q: Where did the boulder come from?A:
Imagine looking at your hand, and knowing nothing of cells, nothing of biochemistry, nothing of DNA. You've learned some anatomy from dissection, so you know yo
Prerequisites: Belief in Belief, Fake Explanations, Fake Causality, Mysterious Answers to Mysterious Questions The failures of phlogiston and vitalism are hist
Once upon a time... This is a story from when I first met Marcello, with whom I would later work for a year on AI theory; but at this point I had not yet accept
I am teaching a class, and I write upon the blackboard three numbers: 2-4-6. "I am thinking of a rule," I say, "which governs sequences of three numbers. The
Previously in series: Lawful Creativity From Robyn Dawes, Rational Choice in an Uncertain World: "Many psychological experiments were conducted in the late 19
It is said that parents do all the things they tell their children not to do, which is how they know not to do them. Long ago, in the unthinkably distant past,
Continuation of: My Wild and Reckless Youth Once upon a time, in my wild and reckless youth, when I knew not the Way of Bayes, I gave a Mysterious Answer to a mysterious-seeming question. Many failures occurred in sequence, but one mistake stands out as most critical: My younger self did not realize that solving a mystery should make it feel less confusing.
Followup to: Failing to Learn from History There is a habit of thought which I call the logical fallacy of generalization from fictional evidence, which deserv
Followup to: Semantic Stopsigns, Mysterious Answers to Mysterious Questions As our tribe wanders through the grasslands, searching for fruit trees and prey, it
Followup to: Semantic Stopsigns, Mysterious Answers to Mysterious Questions, Say Not 'Complexity' Imagine that I, in full view of live television cameras, raise
Followup to: Guessing the Teacher's Password, Artificial Addition A classic paper by Drew McDermott, "Artificial Intelligence Meets Natural Stupidity", critici
"I remember this paper I wrote on existentialism. My teacher gave it back with an F. She'd underlined true and truth wherever it appeared in the essay, probably about twenty times, with a question mark beside each. She wanted to know what I meant by truth."
It is widely recognized that good science requires some kind of humility. What sort of humility is more controversial. Consider the creationist who says: "But
"Believing in Santa Claus gives children a sense of wonder and encourages them to behave well in hope of receiving presents. If Santa-belief is destroyed by t
The classic criticism of the lottery is that the people who play are the ones who can least afford to lose; that the lottery is a sink of money, draining wealth
People are still suggesting that the lottery is not a waste of hope, but a service which enables purchase of fantasy-"daydreaming about becoming a millionaire f
Years ago, I was speaking to someone when he casually remarked that he didn't believe in evolution. And I said, "This is not the nineteenth century. When Darw
Followup to: Tsuyoku Naritai, But There's Still A Chance Right? The Sophisticate: "The world isn't black and white. No one does pure good or pure bad. It
Followup to: But There's Still A Chance Right?, The Fallacy of Gray The one comes to you and loftily says: "Science doesn't really know anything. All you hav
In "What is Evidence?", I wrote: This is why rationalists put such a heavy premium on the paradoxical-seeming claim that a belief is only really worthwhile if you could, in principle, be persuaded to believe otherwise. If your retina ended up in the same state regardless of what light entered it, you would be blind...
Followup to: How To Convince Me That 2 + 2 = 3, Absolute Authority In Absolute Authority, I argued that you don't need infinite certainty: "If you have to ch
Followup to: Infinite Certainty 1, 2, and 3 are all integers, and so is -4. If you keep counting up, or keep counting down, you're bound to encounter a whole
Some responses to Lotteries: A Waste of Hope chided me for daring to criticize others' decisions; if someone else chooses to buy lottery tickets, who am I to disagree? This is a special case of a more general question: What business is it of mine, if someone else chooses to believe what is pleasant rather than what is true?
People go funny in the head when talking about politics. The evolutionary reasons for this are so obvious as to be worth belaboring: In the ancestral environment, politics was a matter of life and death. And sex, and wealth, and allies, and reputation...
Robin Hanson recently proposed stores where banned products could be sold. There are a number of excellent arguments for such a policy-an inherent right of ind
Lady Justice is widely depicted as carrying a scales. A scales has the property that whatever pulls one side down, pushes the other side up. This makes things very convenient and easy to track. It's also usually a gross distortion.
The correspondence bias is the tendency to draw inferences about a person's unique and enduring dispositions from behaviors that can be entirely explained by t
Followup to: Correspondence Bias As previously discussed, we see far too direct a correspondence between others' actions and their inherent dispositions. We s
"...then our people on that time-line went to work with corrective action. Here." He wiped the screen and then began punching combinations. Pa
Black Belt Bayesian (aka "steven") tries to explain the asymmetry between good arguments and good authority, but it doesn't seem to be resolving the comments on Reversed Stupidity Is Not Intelligence, so let me take my own stab at it: Scenario 1: Barry is a famous geologist.
Continuation of: Argument Screens Off Authority In the art of rationality there is a discipline of closeness-to-the-issue -trying to observe evidence that is as near to the original question as possible, so that it screens off as many other arguments as possible. The Wright Brothers say, "My plane will fly."
Yesterday, someone said that my writing reminded them of George Orwell's Politics and the English Language. I was honored. Especially since I'd already though
Followup to: Rationality and the English Language George Orwell saw the descent of the civilized world into totalitarianism, the conversion or corruption of on
Once upon a time I tried to tell my mother about the problem of expert calibration, saying: "So when an expert says they're 99% confident, it only happens abou
Politics is the mind-killer. Debate is war, arguments are soldiers. There is the temptation to search for ways to interpret every possible experimental result
Followup to: Update Yourself Incrementally Yesterday I talked about a style of reasoning in which not a single contrary argument is allowed, with the result th
There are two sealed boxes up for auction, box A and box B. One and only one of these boxes contains a valuable diamond. There are all manner of signs and portents indicating whether a box contains a diamond; but I have no sign which I know to be perfectly reliable.
Yesterday I discussed the dilemma of the clever arguer, hired to sell you a box that may or may not contain a diamond. The clever arguer points out to you that
Followup to: The Bottom Line, What Evidence Filtered Evidence? In "The Bottom Line", I presented the dilemma of two boxes only one of which contains a diamond,
Followup to: The Bottom Line, Rationalization You are, by occupation, a campaign manager, and you've just been hired by Mortimer Q. Snodgrass, the Green candid
A few years back, my great-grandmother died, in her nineties, after a long, slow, and cruel disintegration. I never knew her as a person, but in my distant chi
Followup to: The Third Alternative, The Meditation on Curiosity While I disagree with some views of the Fast and Frugal crowd-IMO they make a few too many lemons into lemonade-it also seems to me that they tend to develop the most psychologically realistic models of any school of decision theory.
Many Christians who've stopped really believing now insist that they revere the Bible as a source of ethical advice. The standard atheist reply is given by Sam
It happens every now and then, that the one encounters some of my transhumanist-side beliefs-as opposed to my ideas having to do with human rationality-strange,
"One of your very early philosophers came to the conclusion that a fully competent mind, from a study of one fact or artifact belonging to any given universe,
Followup to: Entangled Truths, Contagious Lies Judge Marcus Einfeld, age 70, Queens Counsel since 1977, Australian Living Treasure 1997, United Nations Peace Award 2002, founding president of Australia's Human Rights and Equal Opportunities Commission, retired a few years back but routinely brought back to judge important cases...
Followup to: Entangled Truths, Contagious Lies If you once tell a lie, the truth is ever after your enemy. I have previously spoken of the notion that, the tru
I remember the exact moment when I began my journey as a rationalist. It was not while reading Surely You're Joking, Mr. Feynman or any existing work upon ratio
An oblong slip of newspaper had appeared between O'Brien's fingers. For perhaps five seconds it was within the angle of Winston's vision. It was a photograph,
Followup to: Belief in Belief I recently spoke with a person who... it's difficult to describe. Nominally, she was an Orthodox Jew. She was also highly intel
Continuation of: No, Really, I've Deceived MyselfFollowup to: Dark Side Epistemology I spoke yesterday of my conversation with a nominally Orthodox Jewish wom
Followup to: Belief in Self-Deception Moore's Paradox is the standard term for saying "It's raining outside but I don't believe that it is." HT to painquale on MetaFilter. I think I understand Moore's Paradox a bit better now, after reading some of the comments on Less Wrong.
Followup to: Moore's Paradox, Doublethink I don't mean to seem like I'm picking on Kurige, but I think you have to expect a certain amount of questioning if yo
Suppose I spin a Wheel of Fortune device as you watch, and it comes up pointing to 65. Then I ask: Do you think the percentage of African countries in the UN is above or below this number? What do you think is the percentage of African countries in the UN?
Suppose you ask subjects to press one button if a string of letters forms a word, and another button if the string does not form a word. (E.g., "banack" vs. "banner".) Then you show them the string "water". Later, they will more quickly identify the string "drink" as a word.
Some early experiments on anchoring and adjustment tested whether distracting the subjects-rendering subjects cognitively "busy" by asking them to keep a lookou
One of the single greatest puzzles about the human brain is how the damn thing works at all when most neurons fire 10-20 times per second, or 200Hz tops. In ne
Whenever someone exhorts you to "think outside the box", they usually, for your convenience, point out exactly where "outside the box" is located. Isn't it fun
Followup to: Cached Thoughts, The Virtue of Narrowness Since Robert Pirsig put this very well, I'll just copy down what he said. I don't know if this story is based on reality or not, but either way, it's true. He'd been having trouble with students who had nothing to say.
Suppose I told you that I knew for a fact that the following statements were true: If you paint yourself a certain exact color between blue and green, it will r
When I try to introduce the subject of advanced AI, what's the first thing I hear, more than half the time? "Oh, you mean like the Terminator movies / the Matri
What is true of one apple may not be true of another apple; thus more can be said about a single apple than about all the apples in the world. -Twelve Vir
I recently attended a discussion group whose topic, at that session, was Death. It brought out deep emotions. I think that of all the Silicon Valley lunches I
"Over the past few years, we have discreetly approached colleagues faced with a choice between job offers, and asked them to estimate the probability that they
From pp. 55-56 of Robyn Dawes's Rational Choice in an Uncertain World. Bolding added. Norman R. F. Maier noted that when a group faces a problem, the natural
In lists of logical fallacies, you will find included "the genetic fallacy"-the fallacy attacking a belief, based on someone's causes for believing it. This is, at first sight, a very strange idea-if the causes of a belief do not determine its systematic reliability, what does?
The affect heuristic is when subjective impressions of goodness/badness act as a heuristic-a source of fast, perceptual judgments. Pleasant and unpleasant feel
Followup to: The Affect Heuristic With the expensive part of the Hallowthankmas season now approaching, a question must be looming large in our readers' minds:
Followup to: Evaluability "Psychophysics", despite the name, is the respectable field that links physical effects to sensory effects. If you dump acoustic energy into air-make noise-then how loud does that sound to a person, as a function of acoustic energy?
The affect heuristic is how an overall feeling of goodness or badness contributes to many other judgments, whether it's logical or not, whether you're aware of
Followup to: The Halo Effect Suppose there's a heavily armed sociopath, a kidnapper with hostages, who has just rejected all requests for negotiation and annou
Followup to: Superhero Bias Yesterday I discussed how the halo effect, which causes people to see all positive characteristics as correlated-for example, more
Followup to: The Affect Heuristic, The Halo Effect Many, many, many are the flaws in human reasoning which lead us to overestimate how well our beloved theory
Followup to: Affective Death Spirals Once upon a time, there was a man who was convinced that he possessed a Great Idea. Indeed, as the man thought upon the G
Followup to: Resist the Happy Death Spiral Every now and then, you see people arguing over whether atheism is a "religion". As I touched on in Purpose and Pra
Followup to: Uncritical Supercriticality Early studiers of cults were surprised to discover than when cults receive a major shock-a prophecy fails to come true
Followup to: Uncritical Supercriticality One morning, I got out of bed, turned on my computer, and my Netscape email client automatically downloaded that day's
Did you ever wonder, when you were a kid, whether your inane "summer camp" actually had some kind of elaborate hidden purpose-say, it was all a science experiment and the "camp counselors" were really researchers observing your behavior? Me neither.
Followup to: Correspondence Bias, Affective Death Spirals, The Robbers Cave Experiment Cade Metz at The Register recently alleged that a secret mailing list of
Followup to: Tsuyoku Naritai, Reversed Stupidity is not Intelligence The criticism is sometimes leveled against rationalists: "The Inquisition thought they ha
Followup to: Guardians of the Truth Like any educated denizen of the 21st century, you may have heard of World War II. You may remember that Hitler and the Na
Followup to: Every Cause Wants To Be A Cult, Guardians of the Truth "For skeptics, the idea that reason can lead to a cult is absurd. The characteristics of
Followup to: Every Cause Wants To Be A Cult A novice rationalist studying under the master Ougi was rebuked by a friend who said, "You spend all this time
Solomon Asch, with experiments originally carried out in the 1950s and well-replicated since, highlighted a phenomenon now known as "conformity". In the class
Followup to: Asch's Conformity Experiment The scary thing about Asch's conformity experiments is that you can get many people to say black is white, if you put
Followup to: The Modesty Argument, The "Outside the Box" Box, Asch's Conformity Experiment Asch's conformity experiment showed that the presence of a single di
Followup to: Every Cause Wants To Be A Cult, Lonely Dissent In the modern world, joining a cult is probably one of the worse things that can happen to you. Th
I just finished reading a history of Enron's downfall, The Smartest Guys in the Room, which hereby wins my award for "Least Appropriate Book Title". An unsurprising feature of Enron's slow rot and abrupt collapse was that the executive players never admitted to having made a large mistake.
When I was very young-I think thirteen or maybe fourteen-I thought I had found a disproof of Cantor's Diagonal Argument, a famous theorem which demonstrates tha
Casey Serin, a 24-year-old web programmer with no prior experience in real estate, owes banks 2.2 million dollars after lying on mortgage applications in order
Once, when I was holding forth upon the Way, I remarked upon how most organized belief systems exist to flee from doubt. A listener replied to me that the Jesuits must be immune from this criticism, because they practice organized doubt: their novices, he said, are told to doubt Christianity; doubt the existence of God; doubt if their calling is real; doubt that they are suitable for perpetual vows of chastity and poverty.
What is true is already so. Owning up to it doesn't make it worse. Not being open about it doesn't make it go away. And because it's true, it is what is there t
"The first virtue is curiosity." -The Twelve Virtues of Rationality As rationalists, we are obligated to criticize ourselves and question our beliefs..
Traditional Rationality is phrased in terms of social rules, with violations interpretable as cheating-as defections from cooperative norms. If you want me to
"When you surround the enemy Always allow them an escape route. They must see that there is An alternative to death." -Sun Tzu, The Art of War, Cloud Ha
Followup to: Make an Extraordinary Effort, The Meditation on Curiosity, Avoiding Your Belief's Real Weak Points "It ain't a true crisis of faith unless things
Followup to: The Failures of Eld Science, Crisis of Faith The room in which Jeffreyssai received his non-beisutsukai visitors was quietly formal, impeccably ap
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