Some while ago, Peter McIntyre and Jesse Avshalomov compiled a list of concepts they deemed worth knowing. I can imagine that many are pretty well known within EA, but I’ll go out on a limb and say I woudn‘t be surprised if most EAs will find more than one useful new concept. https://conceptually.org/concepts

Consilience

The principle that evidence from independent, unrelated sources can "converge" on strong conclusions

This word can arguably be used to describe the "Many Weak Arguments" aspect of the "Many Weak Arguments vs. One Relatively Strong Argument" post. JonahSinick pointed that out in that post.

Why this is interesting
Consilience is important for evaluating claims. There's a fair bit of historic discussion and evidence now that shows how useful it can be to get a variety of evidence from many different sources.

Nobel Cause Corruption

From Wikipedia:

Noble cause corruption is corruption caused by the adherence to a teleological ethical system, suggesting that people will use unethical or illegal means to attain desirable goals, a result which appears to benefit the greater good. Where traditional corruption is defined by personal gain, noble cause corruption forms when someone is convinced of their righteousness, and will do anything within their powers to achieve the desired result. An example of noble cause corruption is police misconduct "committed in the name of good ends" or neglect of due process through "a moral commitment to make the world a safer place to live."

Why this is interesting
I think one serious concern around consequentialist thought is that it can be used in dangerous ways. I think this term describes some of this, and the corresponding literature provides examples that seem similar to what I can expect future people to follow who misuse EA content.

Governance

In political science literature, "governance" refers to how something is overseen and managed whether or not that's done by Government. For example, if your AI system has to comply with a few regulations, but you're also responsible to your company's ethics board and shareholders, that's all governance.

Relevant for

EAs in politics, policy or institutional change. Particularly useful for EAs interested in AI policy where a wider conception of governance is arguably much more desirable than direct government regulation.

Endogenous institutions

In political and economic literature, institutions include formal groups (eg the Civil Service, the Church of England, the monarchy) but also the overall "rules of the game" (eg to what extent politicians are comfortable accepting bribes/gifts/political donations in exchange for political influence). These rules affect the people "playing the game" eg lobbyists and politicians, but they're also created by them.

Relevant for

EAs working on politics, lobbying or institutional change.

The Cooperative Principle

The cooperative principle describes how people achieve effective conversational communication in common social situations—that is, how listeners and speakers act cooperatively and mutually accept one another to be understood in a particular way.

There are 4 corresponding maxims. I think the main non-obvious ones are:

Maxim of quantity:

1. Make your contribution as informative as is required (for the current purposes of the exchange).
2. Do not make your contribution more informative than is required.

Maxim of relevance

1. Be relevant to the discussion. (For instance, when responding to, "What would you like for lunch" and you respond "I would like a sandwhich"; you are expected to be responding to that very question, not to be making an unrelated statement.)

I think this video explains this well.

Why this is interesting
I've definitely been in conversations where bringing up maxims of quantity and relevance would have been useful to bring up. Conversation and discussion can be quite difficult. We do a lot of that.

Deepity

The term refers to a statement that is apparently profound but actually asserts a triviality on one level and something meaningless on another. Generally, a deepity has (at least) two meanings: one that is true but trivial, and another that sounds profound, but is essentially false or meaningless and would be "earth-shattering" if true.

Why this is interesting
I mostly think this is just a great phrase to describe a lot of difficult language I occasionally see get used in moral discussions.