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by Antoine de Scorraille
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11

  1. I really like dimensional analysis. It's a simple and powerful trick, almost magical, that allows you to distinguish between plausible and chimerical formulas.
  2. I really like the type signature. It's a simple but ontologically important change for classifying different objects. [1]
  3. I really like computational complexity, and its marketing version "Does it scale?" It's a simple but powerful trick for understanding and designing systems and rules. [2]
  4. …

Let's list our ‘intellectual lifehacks’ here, i.e., elements of knowledge that have properties like. :

  • Very general
  • Simple to apply, but powerful

I don't have a proper definition other than ‘I feel like it’ to the question ‘Does this count as an intellectual lifehack?’, but I'd like to make it clear that I'm setting the bar very high. I hope you'll be able to connect the dots with n=3... Anyway, share and discuss!

Hereby, our intellectual lifehacks repo:

  1. ^

    See: How to keep the essence of a theory by looking at the type signature, or to make progress on ontologically unsolved questions

  2. ^

    See: How to import such intellectual lifehack in another intellectual field

Rationality
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Intellectual lifehacks repo
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ashtree

40
  • If something takes longer than expected to get to an answer, think about how you could have seen the problem to be able to solve it faster to be able to solve it faster in the future[1].
    • As an extension, optimize everything. If something is slow and you do it often enough, doing it faster is worth it. Relevant XKCD.[2]
  • Flip a coin if you are struggling to decide between option in a situation where there are relatively low stakes. This exposes to you your gut instinct immediately, which is more than good enough most times, and it is far faster than logically finding an answer.
  1. ^

    e.g. the whole strategy of "dynamic programming", write a recursive solution, then memoize it, then reduce the amount of memory if you don't use it anymore. This works because you have changed your perspective from what clever thing can I do to how can I solve this with a smaller subproblem.

  2. ^

    This also applies to physical actions like walking and opening doors. Most people do these slowly, but since you spend so much time doing them, it is extremely worth it to focus on what you're doing.

[-]daijin32

disagree with the everything part of optimize everything. instead we need

  • a heuristic to determine if something is worth optimizing. i propose a back-of-envelope calculation of how much time you will spend on this in the future; or in practice I go 'have i done this three times?'
  • ways of doing things that are optimal in the first place: cache it if it's free to cache; write down the instructions before implementing.
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2ashtree
Did you see the XKCD? The chart there gives a good heuristic because most things you do that are worth optimizing are things you do at some interval. I don't understand your second point. My guess at an interpretation is basically look up the optimal solution, but I don't think that makes sense with caching.
1daijin
I did see the XKCD and I agree haha, I just thought your phrasing implied 'optimize everything (indiscriminately)'. When I say caching I mean retaining intermediate results and tools if the cost to do so is near free.

Cole Wyeth

31

Bayes rule

Berkson's paradox

Goodhart's law

Efficient market hypothesis

Algon

20

Consistency check: After coming up with a conclusion, check that it's consistent with other simple facts you know. This lets you catch simple errors very quickly.
Give an example: If you've got an abstract object, think of the simplest possible object which instantiates it, preferably one you've got lots of good intuitions about. This resolves confusion like nothing else I know. 
Proving too much: After you've come up with a clever argument, see if it can be used to prove another claim, ideally the opposite claim. It can massively weaken the strength of arguments at little cost.
Prove it another way: Don't leave things at one proof, find another. It shines light on flaws in your understanding, as well as deeper principles. 

Are any of these satisfactory?

[-]daijin30

proving too much comes from Scott Alexander's wonderful blog, slate star codex and i have used it often as a defense to poor generalizations. seconded.

'consistency check' seems like a sanity baseline and completely automatic; its nice to include but not particularly revelatory imo.

'give it an example' also seems pretty automatic.

'Prove it another way' is useful but expensive, so less likely to be used if you're moving fast.

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2Algon
I think I heard of proving too much from the sequences, but honestly, I probably saw it in some philosophy book before that. It's an old idea.  If automatic consistency checks and examples are your baseline for sanity, then you must find 99%+ of the world positively mad. I think most people have never even considered making such things automatic, like many have not considered making dimensional analysis automatic. So it goes.  Which is why I recommended them. Also, I think you can almost always be more concrete when considering examples, use more of your native architecture. Roll around on the ground to feel how an object rotates, spend hours finding just the right analogy to use as an intuition pump.  For most people, the marginal returns to concrete examples are not diminishing.   Prove another way is pretty expensive in my experience, sure. But maybe this is just a skill issue? IDK.

Dave5

10

Dimensional analysis is in instance of type signature checking, as fully understood. Unfortunately very few type systems for existing programming languages support the type transformations necessary to implement it directly.

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[-]Cole Wyeth20

It seems that lesswrong was (before it became mostly AI content) essentially just a massive compilation of such intellectual life hacks. If you filter by the right tags (Rationality?) it should still be usable for this purpose. Have you determined that there is not currently a good centralized table of this kind of content?

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[-]Richard_Kennaway20

The Sequences? Not quite what you're looking for, but that's what I have always thought of as the essentials of LW (before the AI explosion).

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[-]Celarix10

Why, the Practical tag (https://www.lesswrong.com/w/practical) has a lot of cool stuff like this.

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[-]Antoine de Scorraille*10

On a quick search, I couldn't find such a repo. I agree that this is/was the heart of Lesswrong, but what I'm aiming for is more specific than ‘any cool intellectual thing’. A lot of LW's posts are about contrarian viewpoints, or very particular topics. I'm looking for well-known but surprising stuff, to develop common knowledge.

Should feel like: ‘OMG, everyone should know [INSERT YOUR TRICK]’

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