The first book of rationality

This is part 1 of 6 in my series of summaries. See this post for an introduction.



Part I

Map and Territory



T
his part introduces the Bayesian ideas of belief, evidence, and rationality. Ideally, our theories should function like maps for navigating the world – these are proper beliefs. In practice this isn’t always the case, due to cognitive bias.

Biases come in different forms. A “statistical bias” is when you learn from consistently unrepresentative samples of data, leading to worse predictions. A cognitive bias is a systematic error in how we think – which can skew our beliefs so that our beliefs less accurately represent the facts, or skew our decision-making so that we less reliably achieve our goals. When the word “bias” is used in this text, it will mostly refer to cognitive bias. Rationality is about forming the best beliefs and making the best choices you can with the evidence you have and the situation you are in. It is therefore the project of overcoming cognitive bias.

The idea of rationality studied by mathematicians, psychologists and social scientists is different from the Hollywood stereotype of the “rationalist” who suppresses all emotion and intuition. In reality, there are cases where it helps to take your feelings into account when deciding, and to avoid overthinking things. A rationalist would use “System 1” (fast implicit cognition) processes when they are reliable, while keeping in mind that his/her gut intuitions aren’t a reliable guide for when to trust System 1. Hence the need for “System 2” (slow explicit cognition) processes.

The sciences of mind tell us that biases often result when our brains use shortcuts known as cognitive heuristics to guess at the right answer. They often work, but can also lead us to make predictable mistakes. Researchers have discovered many faces of human bias, including people’s tendency not to notice their own biases! To do better, we need a systematic understanding of why good reasoning works and of how the brain falls short of it. This is the approach of “Rationality: From AI to Zombies”.



1

Predictably Wrong

This chapter talks about cognitive bias in general, as a feature of our minds’ structure.

Rationality refers to the art of making one’s mental map correspond to the territory (epistemic rationality) and achieving one’s values (instrumental rationality). In other words, epistemic rationality deals with systematic methods of improving the accuracy of our beliefs and finding out the truth, like Bayesian probability theory. Instrumental rationality deals with systematic methods of making the world more as we’d like it to be and accomplishing our goals, for example by using decision theory. We use these methods because we expect them to systematically work, but they are not inherent to the concept of rationality. And being rational as a human involves more than just knowing the formal theories; it is not realistic for people to fully obey the mathematical calculations of the Bayesian laws underlying rational belief and action. Nevertheless, we can still strive to be less wrong and win more.

Contrary to popular belief, rationality does not oppose all emotion. It can either intensify or diminish feelings, depending on how the world is, since our emotions arise from our models of reality. It is allowed to care and feel strongly, as long as it is not opposed by the truth. For example, a rational belief that something good has happened, leads to rational happiness. When something terrible happens, it is rational to feel sad. Remember: “That which can be destroyed by the truth should be”, as P.C. Hodgell said, but also “that which the truth nourishes should thrive.”

Three main reasons why we seek out truth (i.e. epistemic rationality) are: firstly, for curiosity; secondly, for practical utility (knowing how to effectively achieve goals); and thirdly, for intrinsic value. Pure curiosity, as an emotion, is not irrational (see above). Instrumentally, you have a motive to care about the truth of your beliefs regarding anything you care about. In this case, truth serves as an outside verification criterion. Treating rationality as a moral duty, however, can be problematic if it makes us overly dogmatic in our approach to proper modes of thinking. Nonetheless, we still need to figure out how to avoid biases.

Biases present obstacles to truth produced by the shape of our mental machinery, and insofar we care about truth, we should be concerned about such obstacles. Our brains are not evolutionarily optimized to maximize epistemic accuracy. Biases don’t arise from brain damage or adopted moral duties, but are universal in humans. Note that a bias is not the same as a mistake (i.e. an error in cognitive content, like a flawed belief), but can result in mistakes. The truth is a narrow target, and the space of failure is much wider; thus what we call a “bias” is less important than improving our truth-finding techniques. 

The availability heuristic is when we judge the probability or frequency of an event by ease of retrieval from memory (i.e. how easily examples of it come to mind). By not taking into account that some pieces of evidence are more memorable or easier to come by than others, this leads to biased estimates. Therefore we tend to underestimate the likelihoods of events that haven’t occurred recently (and may even consider them “absurd”) while we overestimate the frequency of events that receive more attention. For example, homicide is less common than we perceive, and we neglect the risk of major environmental hazards. Selective reporting by the media is a major cause of this.

The conjunction fallacy is when we assume that a more detailed description is more plausible, even though probability theory says that the joint probability of X and Y must be equal to or less than the probability of Y. In mathematical terms: P(X&Y) ≤ P(Y). For example, the set of accountants who play jazz is a subset of all people who play jazz. Yet psychology experiments have found that subjects on average rate the statement “Linda is a bank teller and is active in the feminist movement” as more probable than “Linda is active in the feminist movement.” This is partly because subjects use a judgment of representativeness to judge the probability of something by how typical it sounds.

To avoid the conjunction fallacy, you have to notice the word “and”, and then penalize the probability of the scenario. Feel every added detail as a burden. For each independent detail, ask where it came from, and how you know it.

The planning fallacy is when people underestimate how long a project will take to finish (and ignore potential unexpected catastrophes). We tend to envision that everything will go as expected and overestimate our efficiency at achieving a task. Reality usually delivers results somewhat worse than our planned “worse case”. This helps explain why so many construction projects go overbudget. It can be countered by an outside view – asking how long it took to finish broadly similar projects in the past. Avoid thinking about your project’s special unique features.

The illusion of transparency is when we expect others to understand what we mean by our words, because it seems obvious to us. We know what our own words mean. Yet our words are more ambiguous than we think: we overestimate how often others understand our intentions, and we underestimate differences in interpretation. Experimental results have confirmed this: for example, when given ambiguous sentences to speak in front of an audience (like “the man is chasing a woman on a bicycle”), subjects thought that they were understood in 72% of the cases, but they were actually understood in 61% of the cases.

We are biased to underestimate inferential distances (the length of a chain of reasoning needed to communicate an explanation to another person), because in the ancestral environment you were unlikely to be more than one inferential step away from anyone else. Everyone then had shared background knowledge – not so today. Thus we tend to explain only the last step of an argument and not every step that must be taken from our listeners’ premises. This could be why scientists today have difficulty in communicating new knowledge about complicated subjects to outsiders. A clear argument should start from what the audience already accepts.

Unlike mice or other animals, we humans can think about our thinking processes, reason about our reasoning, and make separate mental buckets for the map and territory. We can understand how our eyes and visual cortexes enable us to see light, and thus we can distinguish between senses and reality and recognize optical illusions. We can even apply reflective corrections to our systematic errors. (Science is one such process.) So although our minds are flawed lenses, this ability to see our own flaws and apply second-order corrections to biased first-order thoughts makes us more powerful.


2

Fake Beliefs

In this chapter we look at ways that one’s expectations can come apart from one’s professed beliefs. Errors come not only from our minds’ structure, but can take the form of our minds’ contents, such as bad habits and bad ideas that have been invented or evolved.

Not all beliefs are directly about sensory experiences, but beliefs should “pay rent” in anticipations of experience. Always ask which experiences to anticipate and which not to anticipate (instead of “what statements should I believe?”). For example, if you believe phlogiston is the cause of fire, then what do you expect to see happen because of that? What does this belief not allow to happen? Beliefs should infer causes behind sensory experience, or else they end up floating (detached from reality). Arguments about floating networks of belief can go on forever. It may sound like two people are disagreeing over whether a piece in an art museum is “great art”, but they probably do not differ in terms of anticipated experiences: both would predict lots of artists talking about it and being influenced by it, and also predict that most casual museum visitors would not call it beautiful.

Yudkowsky writes a parable about a society of people forced to live underground for centuries. In this world, the sky is only a legend, and people are divided over whether this “sky” is blue or green. Taking on a belief has acquired social implications, and the result is a variety of compromises to truth-seeking. The Green faction and Blue faction vote differently and have at times been violent toward each other. One day, an explorer in the upper caverns discovers an opening to the sky, and various citizens finally see the sky’s true color. However, not all react the same way. The scientists are the ones who are excited to explore and learn about this new outside world.

Belief-as-anticipation can diverge from cognitive behavior that protects floating propositional beliefs or self-image. This manifests as “belief in belief”: believing that you ought to believe. Hence people can anticipate in advance which experimental results they will need to excuse; for example, someone claims that there is a dragon in their garage, yet they avoid falsification. If you look for the dragon, the person will say “it’s an invisible dragon!” Can we hear heavy breathing? “It’s an inaudible dragon!” and so on. This indicates that some part of their mind knows what’s really going on. They do not anticipate as if the dragon were real, but they may honestly believe that they believe there is a dragon – perhaps because they think it virtuous or beneficial to believe. In addition, the person will deny that they only believe in belief because it isn’t virtuous to believe in belief.

When somebody’s anticipations get out of sync with what they believe they believe, point out how their hypothesis is vulnerable to falsification. For example, imagine someone says “I don’t believe artificial intelligence is possible because only God can make a soul.” You can reply that either their religion allows for AI to happen, or that us building an AI would disprove their religion. One possible outcome is that they will backpedal or say “let’s agree to disagree on this” – but Aumann’s Agreement Theorem shows that if two honest Bayesian rationalists with common priors disagree, at least one is doing something wrong. (Ideally, the two agents would update on each other’s beliefs until they reach agreement.)

When parents can’t verbalize an object-level justification or want their child to stop asking questions (e.g. about religion), they appeal to “adulthood”, saying things like “you’ll understand when you’re older”. But “adulthood” is more about peer acceptance than about being right. Beware errors in the style of maturity! Dividing the world up into “childish” and “mature” is not a useful way to think, because nobody is done with maturing. And the stars in the night sky are much older than any of us, and future intergalactic civilizations may consider us infants by their standards.

Often people display neutrality or suspended judgment as a way to signal maturity or wisdom, as if they were above the conflict. They fear being embarrassingly wrong or losing their reputation for standing above the fray. However, neutrality is still a definite judgment, and like any judgment it can be wrong! Truth is not handed out in equal parts before a dispute, and refusing to take sides is seldom the right course of action. To care too much about your public image is to limit your true virtue. Prioritize your responsibilities on the basis of limited resources, not wise pretensions.

The claim that religion is a “separate magisterium” or metaphor which cannot be proven or disproven is a lie. Religion originally made claims about the world, but the evidence was stacked against it, so religion made a socially-motivated retreat to commitment (belief in belief). In the past, religions made authoritative claims about everything, from science to law, history, government, sexuality and morality. Only recently have religions confined themselves to ethical claims in an attempt to be non-disprovable, and people still see religion as a source of ethics. But since ethics has progressed over time, the ethical claims in ancient scripture should also be wrong.

Some people proudly flaunt scientifically outrageous beliefs (like pagan creation myths) – not to persuade others or validate themselves, but either to profess or to cheer for their side (akin to marching naked at a pride parade). This is even weirder than “belief in belief”. These people aren’t trying to convince themselves that they take their beliefs seriously, but they just loudly cheer their beliefs, like shouting “Go Blues!” Anticipation-controlling beliefs are proper beliefs, while professing, cheering, and belief-in-belief can be considered improper beliefs.

Another type of improper belief is belief-as-clothing: beliefs that fail to control anticipated experiences can function as group identification (like uniforms do). Once you identify with a tribe (whether a sports team or political side), you passionately cheer for it, and you can’t talk about how the Enemy realistically sees the world. For example, it is considered Un-American in Alabama to say that the Muslim terrorists who flew into the World Trade Center saw themselves as brave and altruistic. Identifying with a tribe is a very strong gut-level emotional force, and people will die for it.

If a normal-seeming statement is not followed by specifics or new information, then it’s likely an applause light telling the audience to cheer. For example: “We need a democratic solution!” Words like “democracy” or “freedom” are often applause lights that are used to signal conformity and dismiss difficult problems, because no one disapproves of them. This also applies to people talking about “balancing risks and opportunities” or solving problems “through a collaborative process” without following it up with specifics. Such statements do not have propositional meaning.


3

Noticing Confusion

This chapter provides an explanatory mechanism of how rationality works, and why it is useful to base one’s behavior on rational expectations and what it feels like to do so.

Like time and money, your anticipation is a limited resource which you must allocate as best you can, by focusing it into whichever outcome actually happens. That way, you don’t have to spend as much time concocting excuses for other outcomes. Post-hoc theories that “explain” all possible outcomes equally well (as used by TV pundits to explain why bond yields always fit their pet market theory) don’t focus uncertainty. But if you don’t know the outcome yet (no one can foresee the future), then you should spend most of your time on excuses for the outcomes you anticipate most.

Evidence is an event entangled by chains of cause-and-effect with a target of inquiry, such that it correlates with different states of the target. The event should be more likely if reality is one way than if reality is another. For example, your belief about your shoelaces being untied is the outcome of your mind mirroring the state of your actual shoelaces via light from the Sun bouncing off your shoelaces and striking the retina in your eye, which triggers neural impulses. If the photons ended up in the same physical state regardless of whether your shoelaces were tied or untied, the reflected light would not be useful evidence about your shoelaces. If your eyes and brain work correctly, then your beliefs will end up entangled with reality, and be contagious (i.e. your beliefs themselves would be evidence). Beliefs that are not entangled with reality are not accurate – but blind faith. This also means that you should conceivably be able to believe otherwise given different observations.

We may accept someone’s personal testimony or hearsay as Bayesian rational evidence, but legal evidence has to meet particular standards (so that it doesn’t get abused by those with power), and scientific evidence must take the form of publicly reproducible generalizations (because we want a reliable pool of human knowledge). This is different still from historical knowledge, which we cannot verify for ourselves. Science is about reproducible conditions rather than the history of a particular experiment. Predictions based on science, even if not yet tested, can be rational to believe. In a way, scientific evidence and legal evidence are subsets of rational evidence.

You require evidence to form accurate beliefs, but how much depends on (a) how confident you wish to be; (b) how a priori unlikely the hypothesis seems; and (c) how large the hypothesis-space is. Thus if you want to be very confident, and you are considering one hypothesis out of many, and that hypothesis is more implausible than the others, you will need more evidence. The quantity of evidence can be measured using mathematical bits, which are the log base ½ of probabilities. For example, an event with 12.5% chance conveys log0.5 (0.125) = 3 bits of information when it happens.

You need an amount of evidence equivalent to the complexity of the hypothesis just to locate it and single it out for attention in the space of possibilities. Before Albert Einstein’s theory of General Relativity was experimentally confirmed by Sir Arthur Eddington, Einstein was confident that the observations would match his theory. This suggests that Einstein already had enough evidence at hand when he first formulated the hypothesis. From a Bayesian perspective, he wasn’t as arrogant as he seemed.

Occam’s Razor is often phrased as “the simplest explanation that fits the facts”, but what does it mean for a theory to be complex? With formalisms of Occam’s Razor, the complexity of descriptions is measured by Solomonoff Induction (the length of the shortest computer program that produces the description as output) or Minimum Message Length (the shortest total message as a function of a string describing a code plus a string describing the data in that code). It is not measured in English sentences. To a human, “Thor” feels like a simpler explanation for lightning than Maxwell’s Equations, but that’s because we don’t see the full complexity of an intelligent emotional mind. Of course, it is easier to write a computer program that simulates Maxwell’s Equations than one simulating Thor.

Belief is easier than disbelief because we believe instinctively and require conscious effort to disbelieve. But a rationalist should be more confused by fiction than by reality, for a model that fails to constrain anticipation (by permitting everything and forbidding nothing) is useless. If you are equally good at explaining any outcome, you have zero knowledge. When trying to explain a story, pay attention to the feeling of “this feels a little forced.” Your feeling of confusion is a clue – don’t throw it away. Either your model is false or the story is wrong.

During the Second World War, California governor Earl Warren said that, since there was a lack of sabotage by Japanese-Americans, this was a sign of a Fifth Column (subversive group) existing. But the absence of a Fifth Column is more likely to produce an absence of sabotage! Absence of proof is not proof of absence. However, in Bayesian probability theory, absence of evidence is evidence of absence. If something being present increases your probability of a claim being true, then its absence must decrease it. Mathematically, P(H|~E) < P(H) < P(H|E) where E is evidence for hypothesis H. Whether the evidence is strong or weak depends on how high a likelihood the hypothesis assigns to the evidence.

Due to the fact that P(H) = P(H&E) + P(H&~E) the expectation, on average, of the posterior probability must equal the prior probability. Thus for every expectation of evidence there is an equal and opposite expectation of counterevidence. If you are about to make an observation, then you must, on average, expect to be exactly as confident afterwards as when you started out. So a true Bayesian cannot seek out evidence to confirm their theory, but only to test their theory. Ignoring this is like holding anything an accused witch does or says as proof against her.

People often dismiss social science findings as “what common sense would expect”, because hindsight bias (overestimating how predictable something was) makes it too easy to retrofit these findings into our models of the world. Yet experiments have found that subjects can rationalize both a statement and its opposite. For example, subjects rate the supposed finding that “people in prosperous times spend a larger portion of their income than during recessions” as what they would have expected; but also rate the opposite statement as what they would have expected! Thus hindsight bias leads us to undervalue the surprisingness of scientific findings and the contributions of researchers. It prevents us from noticing when we are seeing evidence that doesn’t fit what we really would have expected.


4

Mysterious Answers

This chapter asks whether science resolves the problems of irrationality for us. Scientific models aim to explain phenomena and are based on repeatable experiments. Science has an excellent track record compared to speculation, hearsay, anecdote, religion, appealing stories, and everything else. But do we still need to worry about biases?

Imagine a square plate of metal placed next to a hot radiator; if you place your hand on the plate and feel that the side adjacent to the radiator is cool and the distant side is warm, why do you think this happens? Saying “because of heat conduction” is not a real explanation unless it constrains anticipation (more so than “magic”). Yet physics students may profess it (rather than measure anything, or admit that they don’t know) and mistakenly think they’re doing science. Normally you’d anticipate the side of the plate next to the radiator to feel warmer; in this case, the plate was just turned around. What makes something a real explanation is not the literary genre of the words you use, or whether it sounds “scientific” enough, but whether it can explain only the observations that actually happened. A fake explanation is one that can explain any observation.

Verbal behavior is not intrinsically right or wrong, but it gets you a gold star from the teacher. In schools, students are expected to memorize the answers to certain questions (the “teacher’s password”). For example, if the teacher asks “what is light made of?” the student replies “waves!” But this is a word, not a proper belief or hypothesis. Instead of guessing the password, we need to train students to anticipate experiences and learn predictive models of what is and isn’t likely to happen – or else they’ll get stuck on strange problems and refuse to admit their confusion.

The X-Men movies use words like “genetic code” to signify the literary genre of science. Some people talk about “evolution” to wear scientific attire and identify themselves with the “scientific” tribe. But they don’t ask which outcomes their model prohibits (or realize they even need a model) and therefore they are not using real science. You don’t understand the phrase “because of evolution” unless it constrains your anticipations. Likewise, you shouldn’t automatically reject an idea (like smarter-than-human artificial intelligence) just because it sounds like science fiction.

It is easy for us to think that a theory predicts a phenomenon when it was actually fitted to a phenomenon. Hindsight bias makes fake causality hard to notice. “Phlogiston” was used to explain why fire burned hot and bright, but it made no advance predictions and could explain anything in hindsight (thus it was a fake explanation). In terms of causal Bayes nets, phlogiston double-counts the evidence. This means that if you have a directed acyclic graph like this:

… then counting the forward message from cause to effect and also the backward message from fire being hot to the Phlogiston node is contaminating the forward-prediction of phlogiston theory. You must separate forward and backward messages, and count each piece of evidence only once! To ensure your reasoning about causality is correct, write down your predictions in advance.

A semantic stopsign (aka cognitive traffic signal aka curiosity-stopper) is a failure to consider the obvious next question. Certain words and phrases can act as “stopsigns” to thinking. For example, saying “God!” in response to the paradox of the First Cause, or “Liberal Democracy!” in response to risks from emerging technologies, without further query. They are not actual explanations and don’t help to resolve the issue at hand, but they act as markers saying “don’t ask any questions”. What distinguishes a stopsign is not strong emotion, but how the word is used to halt the question-and-answer chain.

Before biochemistry, the theory of Vitalism postulated a mysterious substance, élan vital, to explain the mystery of living matter. But this was a curiosity-stopper, not an anticipation-controller. It may feel like an explanation, but given “élan vital!” as the answer, the phenomenon is just as mysterious and inexplicable as it was before. When something feels like a mystery, that is a fact about your state of mind, not the phenomenon. Mystery is a property of questions, not answers. Ignorance exists in the map, not in the territory. Don’t cherish your ignorance, as Lord Kelvin did regarding life! Kelvin, a vitalist, proudly made biology into a sacred mystery beyond ordinary science.

The theory of “emergence” (how complex systems arise from the interaction of simple elements) has become popular nowadays, but it’s just a mysterious answer to a mysterious question. It’s fine to say “X emerges or arises from Y” if Y is a specific model with internal moving parts, but saying “Emergence!” as if it were an explanation in its own right does not dissolve the mystery. After learning that a property is emergent, you aren’t able to make any new predictions. It’s like saying, “It’s not a quark!” – because every phenomenon above the quark-level is “emergent”. It functions like a fake explanation or semantic stopsign.

Complexity can be a useful concept, but it should not be used as a fake explanation to skip over the mysterious part of your model. Too often people assume that adding complexity to a system they don’t understand (e.g. intelligence) will improve it. If you don’t know how to solve a problem, adding complexity won’t help, because saying “complexity!” doesn’t concentrate your probability mass. It’s better to say “magic” (or “I have no idea”) as a placeholder to remind yourself that there is a gap in your understanding.

What rule governs the sequence 2, 4, 6…? Many of us test our hypotheses by looking for data that fits the hypothesis rather than looking for data that would disconfirm our hypothesis. In the Wason 2-4-6 task, positive bias leads subjects to confirm their hypothesis, rather than try to falsify it by testing negative examples. Thus, only 20% correctly guess the rule. Subjects may test 4, 6, 8 or 10, 12, 14 and hypothesize “numbers increasing by two”, when the rule actually is three numbers in ascending order. Remember that the strength of a hypothesis is what it can’t explain!

You can’t fight fire with fire, nor random chaos with randomness. The optimal strategy when facing uncertainty is still to think lawfully and rationally. If tasked to predict a random sequence of red and blue cards where 70% are blue, the best you can do is to predict blue on every trial (and not 70% of the time!). Yet in an experiment, the subjects acted like they could predict the sequence, and they guessed red about 30% of the time. A random key does not open a random lock just because they are “both random”. Faced with an irrational universe, throwing away your rationality won’t help.

To get things right, “Traditional Rationality” (which lacks Bayesian probability theory and experimental psychology) is not enough, and just leads you to different kinds of mistakes, for example ignoring prior likelihoods, the conjunction fallacy, and so on. Traditional Rationality says you can formulate hypotheses without a reason to prefer them to the status quo, as long as they are falsifiable. But this can waste a lot of time. It takes a lot of rationality to avoid making mistakes. The young Eliezer Yudkowsky erred in predicting that neurons were exploiting quantum gravity.

We fail to learn the historical lesson of science, which is that mundane phenomena used to be mysterious until science solved them. Solving a mystery should make it feel less confusing! Yet alchemy seemed reasonable at the time. Unfortunately we don’t personally experience history. It seems to us now that biology, chemistry and astronomy are naturally the realm of science, but if we had lived through their discoveries and watched mysterious phenomena reduced to mundane, we would be more reluctant to believe the next phenomenon is inherently mysterious.

We sometimes generalize from fictional evidence (for example using the Terminator movies as true prophecies of AI), while failing to be sufficiently moved by actual historical evidence. Our brains aren’t well-equipped to translate dry historical facts into experiences. Perhaps we should imagine living through history, to make humanity’s past mistakes more available (and to be less shocked by the future). Imagine watching mysteries be explained, watching civilizations rise and fall, and being surprised over and over again. Perhaps then we’ll stop falling for Mysterious Answers.

When you encounter something you don’t understand, for example if you don’t know why it rains, you have at least three options: you can Ignore the issue and avoid thinking about it; you can try to Explain it (which sometimes takes a while, and the explanation itself may require an explanation); or you can embrace and Worship the sensation of mysteriousness – which is akin to worshipping your confusion and ignorance. There are more ways to worship something than lighting candles around an altar.

“Science!” is often used as a curiosity-stopper rather than a real explanation. For example, why does flipping a switch turn the light bulb on? “Electricity!” Although science does have explanations for phenomena, it is not enough to simply appeal to “Science!” (this is like “God did it!”). Yet for many people, noting that science has an answer is enough to make them no longer curious about how something works. But if you can’t do the calculations that control your anticipation, why should the fact that someone else knows diminish your curiosity? Be intrigued by the world’s puzzles!

To test your understanding, ask whether you would be able to regenerate the knowledge for yourself if it were deleted from your memory. If not, it’s probably a floating belief or password, and you haven’t really learned anything. If you don’t have enough experience to regenerate beliefs when they are deleted, then do you have enough experience to connect that belief to anything at all? Make the source of your thoughts part of you. If the knowledge is entangled with the rest of the world, this method will allow you to apply it to other domains and update it when needed. Thus, being “truly part of you”, it will grow and change with the rest of your knowledge. When you find and absorb a fountain of knowledge, see what else it can pour.


Interlude: The Simple Truth

THIS ESSAY BY Yudkowsky (hosted on his website yudkowsky.net) is an allegory on the nature of knowledge and belief. Some people would say that the notion of “truth” is naïve, but it would not be wise to abandon the concept of truth. So what do we mean by “X is true”?

Imagine that you are a shepherd in an era before recorded history or formal mathematics, and you want to track your sheep. How could you tell, without spending hours looking, whether there are any sheep grazing in the pasture or whether they are all safely enclosed in the fold?

You could drop a pebble into a bucket each time a sheep leaves the enclosure, and take one pebble out of the bucket for each sheep that returns. When no pebbles are left in the bucket, you can stop searching for the night.

In this analogy, the “sheep” refer to reality, the “bucket” is your belief, and the “pebble level” is its degree of truth-tracking. Beliefs are the thingies that determine your predictions, and reality is the thingy that determines your experimental results.

The pebble-and-bucket method works whether or not you believe in it, because it makes the sheep control the pebbles via interacting with things that interact with the pebbles, so there is a chain of cause-and-effect. Likewise, the correspondence between reality and your beliefs comes from reality controlling your beliefs, not the other way around. And just like you wouldn’t have evolved a mouth if there were no food, you wouldn’t need beliefs if there were no reality. If you think that your beliefs alter your personal reality, you will still fall when you step off a cliff.

Does two sheep plus two sheep really ultimately equal four sheep? Yes. The simple and obvious answer isn’t always the best choice, but sometimes it really is. So hopefully the question seems trivial to you, instead of being a deep mystery.




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