Less Wrong: A Human's Guide to Words

A series on the use and abuse of words; why you can’t define a word any way you like; how human brains seem to process definitions. First introduces the Mind projection fallacy and the concept of how an algorithm feels from inside, which makes it a basic intro to key elements of the LW zeitgeist.

This Channel Includes:

  • 27 articles written by Eliezer Yudkowsky
  • 3.4 hours of audio narrated by George Thomas

Note: Due to its abundant use of math, this package excludes the article Conditional Independence and Naive Bayes.

The Parable Of The Dagger


  1. The Parable Of The Dagger [read now]

    The jester reasoned thusly: "Suppose the first inscription is true. Then the second inscription must also be true. Now suppose the first inscription is false. Then again the second inscription must be true. So the second box must contain the key, if the first inscription is true, and also if the first inscription is false.

  2. The Parable Of Hemlock [read now]

    Followup to: The Parable of the Dagger "All men are mortal. Socrates is a man. Therefore Socrates is mortal." - Aristotle(?) Socrates raised the glass of hemlock to his lips... "Do you suppose," asked one of the onlookers, "that even hemlock will not be enough to kill so wise and good a man?"

  3. Words As Hidden Inferences [read now]

    Followup to: The Parable of Hemlock Suppose I find a barrel, sealed at the top, but with a hole large enough for a hand. I reach in, and feel a small, curved object. I pull the object out, and it's blue-a bluish egg.

  4. Extensions And Intensions [read now]

    Followup to: Words as Hidden Inferences "What is red?""Red is a color.""What's a color?""A color is a property of a thing." But what is a thing? And what's a property? Soon the two are lost in a maze of words defined in other words, the problem that Steven Harnad once described as trying to learn Chinese from a Chinese/Chinese dictionary.

  5. Similarity Clusters [read now]

    Followup to: Extensions and Intensions Once upon a time, the philosophers of Plato's Academy claimed that the best definition of human was a "featherless biped". Diogenes of Sinope, also called Diogenes the Cynic, is said to have promptly exhibited a plucked chicken and declared "Here is Plato's man."

  6. Typicality And Asymmetrical Similarity [read now]

    Yes, you can come up with rationalizations, like "Well, there could be more neighboring species of the robins, which would make the disease more likely to spread initially, etc.," but be careful not to try too hard to rationalize the probability ratings of subjects who didn't even realize there was a comparison going on.

  7. The Cluster Structure Of Thingspace [read now]

    Followup to: Typicality and Asymmetrical Similarity The notion of a "configuration space" is a way of translating object descriptions into object positions. It may seem like blue is "closer" to blue-green than to red, but how much closer? It's hard to answer that question by just staring at the colors.

  8. Disguised Queries [read now]

    At first you might answer that, since you intend to throw this object in the rube bin, you might as well call it a "rube". However, it turns out that almost all bleggs, if you switch off the lights, glow faintly in the dark; while almost all rubes do not glow in the dark.

  9. Neural Categories [read now]

    Followup to: Disguised Queries In Disguised Queries, I talked about a classification task of "bleggs" and "rubes". The typical blegg is blue, egg-shaped, furred, flexible, opaque, glows in the dark, and contains vanadium. The typical rube is red, cube-shaped, smooth, hard, translucent, unglowing, and contains palladium.

  10. How An Algorithm Feels From Inside [read now]

    The standard rationalist view would be that the first person is speaking as if "sound" means acoustic vibrations in the air; the second person is speaking as if "sound" means an auditory experience in a brain. If you ask "Are there acoustic vibrations?" or "Are there auditory experiences?", the answer is at once obvious.

  11. Disputing Definitions [read now]

    I have watched more than one conversation-even conversations supposedly about cognitive science-go the route of disputing over definitions. Taking the classic example to be "If a tree falls in a forest, and no one hears it, does it make a sound?", the dispute often follows a course like this:

  12. Feel The Meaning [read now]

    Followup to: Disputing Definitions When I hear someone say, "Oh, look, a butterfly," the spoken phonemes "butterfly" enter my ear and vibrate on my ear drum, being transmitted to the cochlea, tickling auditory nerves that transmit activation spikes to the auditory cortex, where phoneme processing begins, along with recognition of words, and reconstruction of syntax (a by no means serial process), and all manner of other complications.

  13. The Argument From Common Usage [read now]

    Followup to: Feel the Meaning Part of the Standard Definitional Dispute runs as follows: Albert: "Look, suppose that I left a microphone in the forest and recorded the pattern of the acoustic vibrations of the tree falling. If I played that back to someone, they'd call it a 'sound'!

  14. Empty Labels [read now]

    Followup to: The Argument from Common Usage Consider (yet again) the Aristotelian idea of categories. Let's say that there's some object with properties A, B, C, D, and E, or at least it looks E-ish.

  15. Taboo Your Words [read now]

    In the game Taboo (by Hasbro), the objective is for a player to have their partner guess a word written on a card, without using that word or five additional words listed on the card. For example, you might have to get your partner to say "baseball" without using the words "sport", "bat", "hit", "pitch", "base" or of course "baseball".

  16. Replace The Symbol With The Substance [read now]

    What does it take to-as in yesterday's example-see a "baseball game" as "An artificial group conflict in which you use a long wooden cylinder to whack a thrown spheroid, and then run between four safe positions"?

  17. Fallacies Of Compression [read now]

    Followup to: Replace the Symbol with the Substance "The map is not the territory," as the saying goes. The only life-size, atomically detailed, 100% accurate map of California is California. But California has important regularities, such as the shape of its highways, that can be described using vastly less information-not to mention vastly less physical material-than it would take to describe every atom within the state borders.

  18. Categorizing Has Consequences [read now]

    Followup to: Fallacies of Compression Among the many genetic variations and mutations you carry in your genome, there are a very few alleles you probably know-including those determining your blood type: the presence or absence of the A, B, and + antigens.

  19. Sneaking In Connotations [read now]

    Followup to: Categorizing Has Consequences Yesterday, we saw that in Japan, blood types have taken the place of astrology-if your blood type is AB, for example, you're supposed to be "cool and controlled". So suppose we decided to invent a new word, "wiggin", and defined this word to mean people with green eyes and black hair- A green-eyed man with black hair walked into a restaurant.

  20. Arguing "By Definition" [read now]

    But visible, known, widely believed characteristics are rarely the real point of a dispute. Just the fact that someone thinks Socrates's two legs are evident enough to make a good premise for the argument, "Therefore, by definition, Socrates is human!" indicates that bipedalism probably isn't really what's at stake-or the listener would reply, "Whaddaya mean Socrates is bipedal?

  21. Where To Draw The Boundary? [read now]

    Followup to: Arguing "By Definition" The one comes to you and says: Long have I pondered the meaning of the word "Art", and at last I've found what seems to me a satisfactory definition: "Art is that which is designed for the purpose of creating a reaction in an audience."

  22. Entropy, And Short Codes [read now]

    First you ask, "Is the first symbol 1?" If the answer is "yes", you're done: Y is in state 1. This happens half the time, so 50% of the time, it takes 1 yes-or-no question to find out Y's state. Suppose that instead the answer is "No".

  23. Mutual Information, And Density In Thingspace [read now]

    You would end up with the same total you would get if you separately calculated the entropy of Y plus the entropy of Z. There is no mutual information between the two variables, so our uncertainty about the joint system is not any less than our uncertainty about the two systems considered separately.

  24. Superexponential Conceptspace, And Simple Words [read now]

    Followup to: Mutual Information, and Density in Thingspace Thingspace, you might think, is a rather huge space. Much larger than reality, for where reality only contains things that actually exist, Thingspace contains everything that could exist.

  25. Conditional Independence, And Naive Bayes [read now]

    Followup to: Searching for Bayes-Structure Previously I spoke of mutual information between X and Y, I(X;Y), which is the difference between the of the joint probability distribution, H(X,Y) and the entropies of the marginal distributions, H(X) + H(Y).

  26. Words As Mental Paintbrush Handles [read now]

    I'm not a neurologist, but I believe the classical answer is that words point to patterns in clusters of neurons. Everything filed under "apple" slightly rearranges neurons in the "apple" category, including pictures of apples, the taste of an apple, stories about apples, etc.

  27. Variable Question Fallacies [read now]

    Followup to: Words as Mental Paintbrush Handles Albert: "Every time I've listened to a tree fall, it made a sound, so I'll guess that other trees falling also make sounds. I don't believe the world changes around when I'm not looking."Barry: "Wait a minute. If no one hears it, how can it be a sound?"