Jargon

This is a short list of common terms and phrases used on LessWrong.

See also:

• Category:Jargon
• Acronym Finder

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ADBOC

Agree Denotationally, But Object Connotatively

Discussion in When Truth Isn't Enough

AFAICT

As Far As I Can Tell

Affective death spiral

When positive attributions combine with the halo effect in a positive feedback loop.

AGI

Artificial general intelligence

Anti-epistemology

Bad rules for thinking itself, capable of protecting false beliefs.

Beisutsukai

A fictional secret society of Bayesians.

Belief update

What you do to your beliefs, opinions and cognitive structure when new evidence comes along.

Blues, Greens

Roman Empire chariot-racing teams that became part of politics. Used in place of real party names.

See Color politics

CEV

Coherent Extrapolated Volition

Consequentialism

A moral theory in which your choices are based on the consequences of your actions... kinda. Covered in more depth here.

Crisis of faith

What to have when you may have been quite wrong for a long time.

Dark arts

Rhetorical techniques crafted to exploit human cognitive biases. Considered bad behaviour even if the belief you want to communicate is good.

EEA

Environment of Evolutionary Adaptedness

An Evolutionary psychology term synonymous with the more commonly-used "ancestral environment". For humans, refers to the state of tribal bands of hunter-gatherers.

ETA

Edited To Add

FAI

Friendly AI

Fully general counterargument

An argument which can be used to discount any conclusion the arguer does not like.

Fuzzies

The desired but less useful counterpart to utilons. They make you feel you're altruistic and socially contributing.

Hedon

A unit philosophers use to quantify pleasure. (Note: no actual quantifying is done.)

Hollywood rationality

What Spock does, not what actual rationalists do.

IA

Intelligence augmentation

IAWYC

I Agree With Your Conclusion

Generally used when nitpicking, to make it clear that the nitpicks are not meant to represent actual disagreement. Discussed in Support That Sounds Like Dissent.

I don't know

Something that can't be entirely true if you can even formulate a question.

ISTM

It Seems To Me

Kolmogorov complexity

Given a string, the length of the shortest possible program that prints it.

LCPW, Least convenient possible world

To assume that all the specific details will align with the idea against which you are arguing, and that you can't evade a philosophical question by nitpicking details.

Logical rudeness

A response to criticism which insulates the responder from having to address the criticism directly, without appearing to be conventional rudeness.

LW

Less Wrong

Meetup

Groups of Less Wrong members sometimes arrange to meet each other in meat space. Some geographic areas have groups that do this regularly.

Mind-killer

A topic that reliably produces biased discussions, e.g. politics or Pick-Up Artists.

Motivated cognition

Reasoning that starts with its conclusion and works backwards.

OB

Overcoming Bias

One-box

One of the choices for Newcomb's problem.

Omega

A hypothetical superintelligent being, canonically found in Newcomb's problem.

Paperclip maximizer

An AI that has been created to maximise the number of paperclips in the universe. A form of UFAI.

Paranoid debating

A group estimation game in which one player, unknown to the others, tries to subvert the group estimate.

PCT

Perceptual control theory

PD

Prisoner's dilemma

Philosophical zombie or P-Zombie

A creature which looks and behaves indistinguishably from a human down to the atomic level, but is not conscious. The concept is not well-respected on LessWrong.

Priors

What you update from in Bayesian calculations. In practical terms, everything you think you know now.

QALY

Quality-adjusted life year

Rationalist taboo

A technique of reducing what you are talking about: taboo the use of a given word or its synonyms. Particularly useful in arguments over definitions.

Semantic stopsign

A term that looks like an explanation but, on closer examination, doesn't actually explain anything.

Shut up and multiply

How to do a utility calculation without scope insensitivity.

Solomonoff induction

A formalised version of Occam's razor based on Kolmogorov complexity.

Taboo the word ...

This is the technique of Rationalist taboo - whereby you taboo the use of a given word or its synonyms. Particularly useful in arguments over definitions.

Teleology

Discussing an event in a manner that implies it is caused by its future consequences.

tl;dr

Too long; didn't read.

Polite use: one-line summary at top of your long article. Impolite use: dismissive response to another's long piece of writing or unparagraphed slab of text.

Topic that must not be named

When LessWrong was started, Eliezer put a temporary moratorium on discussion of the Singularity or AI. You will see this used in old discussions to allude to these topics.

Two-box

One of the choices for Newcomb's problem.

Tsuyoku naritai

Japanese: "I want to become stronger."

UFAI

Unfriendly AI

Utility function

A utility function assigns numerical values ("utilities") to outcomes, in such a way that outcomes with higher utilities are always preferred to outcomes with lower utilities.

Utilons

Units of utility. Contrast "Fuzzies".

Update

See Belief update.

YMMV

Your Mileage May Vary

See Other-optimizing