Taboo "rationality," please.

* one who reliably wins
* one who can reliably be expected to speak truth

Yeah it must have been getting pretty bad if we got to the point that the word could mean two contradictory things. ;-)

A good reason to take this suggestion to heart: The terms "rationality" and "rational" have a strong positive value for most participants here—stronger, I think, than the value we attach to words like "truth-seeking" or "winning." This distorts discussion and argument; we push overhard to assert that things we like or advocate are "rational" in part because it feels good to associate our ideas with the pretty word.

If you particularize the conversation—i.e., you are likely to get more money by one-boxing on Newcomb's problem, or you are likely to hold more accurate beliefs if you update your probability estimates based solely on the disagreement of informed others—than it is less likely that you will grow overattached to particular procedures of analysis that you have previously given an attractive label.

Definitions of words usually only make much sense in some restricted part of reality, where certain things correlate with certain other things.

For "rationality", it is the case that a certain collection of human mental habits tend to correlate with success in a wide field of endeavors, and that the primary reason for this is that the human mind is an example of a somewhat broken truth seeker (i.e. a partially accurate map), and in many cases mending the map causes the human in question to better achieve his/her goals.

However, there are some contexts in which "mending" the map does not cause the human to better achieve his/her goals. These situations (such as the man who would do best to assign probability zero to his wife cheating on him, for example) reflect the fact that the human mind is not a perfect disembodied AGI. We leak our preferences out in our body language and mannerisms. We have preferences that supervene on our own mental states (making the map a self-referential one). We find it hard to motivate ourselves to act, and sometimes believing that things are better than they really are can motivate us better.

It is thus the case that rationality-as-winning can be very weird in general. There are possible worlds where dark-side epistemology is good for you. Imagine an impoverished medieval peasant being confronted with the truth about his existence - religion was probably the only thing that made life even remotely worth living. It is only the empirical content of this world that makes rationality-as-winning look a lot like rationality-as-accurate-map, and thus allows us to further our goals in a particularly general and simple way. Eliezer's observations about dark side epistemology and reality as an interconnected web, and about how if you abandon rationality-as-accurate-map because you think it will be good for you (i.e. you delude yourself), you can never be sure that there isn't something crucial you've missed - something like cryonics - that will change the entire calculation. This tells me that once the optimal policy on self-delusion looks (naively) like "have an almost accurate map", then the true optimal policy (taking black swans like cryonics into account) is to have a completely accurate map. Thus the shift from a world where map-accuracy and winningness are not the same thing to one where they're identical a posteriori is a nonlinear shift, and in my mind this legitimizes the use of the term "rationality".

It is my opinion that the balance towards rationality-as-winning being rationality-as-accurate-map has only just tipped. The possibility of a technological singularity, of technological immortality, of technological utopia and the insurance that cryonics offers really do tip the balance I think. Without these, even in a comfortable world like the world of the US/EU today, most people's rationality-as-winning probably involves a lot of irrationality-as-inaccurate-map and dark side epistemology to perform the cover up.

Human psychology is so weird that having correct beliefs actually works against winning reliably. For example, having correct beliefs requires you to make a special effort to seek evidence that your beliefs are wrong, making you less certain than others and therefore less determined.

Re: Are there any others?

Well, yes. Rationality, the way I think of it, isn't about "winning" or "truth-seeking".

If you think of a cybernetic diagram of an organism - like this:

Sensory input -> Computations -> Motor output

...then I think "rationality" needs to be confined to the middle unit. It is a computational process. You might need some motor output in order to be able to detect it - but that isn't part of rationality itself.

Truth-seeking is a goal. It is one goal among the many possible that it is possible to rationally pursue. Rational agents often adopt truth-seeking as a proximate goal - whatever they want to do - but embracing false beliefs is sometimes rational too - it depends on what your goal is.

For me, rationality has a lot to do with the valid use of inductive and deductive reasoning in pursuit of a goal.

I think it's fine to use the terms if you say what you mean by them, and not especially bad to use them even if you don't. We can't define all our terms. Why single those ones out as problematic? More potential for confusion lurks in the words we're not watching as closely.

I will not cease using perfectly good words.

I will, however, ask that people be prepared to define and explain the words when they use them. Words are problematic only when they become empty signifiers, labels attached to nothing.

I think we should be careful of elegant variation, which can be awkward and introduce ambiguity. Rather than simply using sobriquets or synonyms like "truth-seeking", "lucidity", or "ratiocination", we might do better to interrogate each other on what rationality is, and make frequent, almost-repetitive reference to the essentials of rationality. This would work especially well for people with idiosyncratic definitions.

There was a (tiny) movement about 20 years ago to get people to stop using the word "is". Usually, an "is" renders a judgement while concealing the reasons: "Cindy is sweet. The GPL is stupid and destructive."

I think I can make as good a case for banning "is" as for banning "rationality". And if we should ban "is", what shouldn't we ban? Can you name any words that shouldn't be banned?

Maybe we should just point.

Are there any others?

Eliezer's not saying the obvious so I will...

Hitting small targets in large search spaces to produce coherent real-world effects that steer reality into regions that are higher in your preference ordering.

Very good idea. Too many here seem to have idiosyncratic definitions of these terms.

I agree with this point generally but it is difficult to find specific examples because they will be heavily context-dependent. Ratiocinative is one probably underused word, as is lucid.

Rationalist: one who seeks to only have contagious beliefs, that is, beliefs which are tightly correlated/entangled with reality.

Error reduction?

Probability or possibility pruning?

Parachute venting? (The mechanism for letting hot air out of an air balloon to bring it back to the ground).