Explanations for Less Wrong articles that you didn't understand

Kaj_Sotala

I'm struggling to understand anything technical on this website. I've enjoyed reading the sequences, and they have given me a lot to thing about. Still, I've read the introduction to Bayes theorem multiple times, and I simply can't grasp it. Even starting at the very beginning of the sequences I quickly get lost because there are references to programming and cognitive science which I simply do not understand.

Thinking about it, I realized that this might be a common concern. There are probably plenty of people who've looked at various more-or-less technical or jargony Less Wrong posts, tried understanding them, and then given up (without posting a comment explaining their confusion).

So I figured that it might be good to have a thread where you can ask for explanations for any Less Wrong post that you didn't understand and would like to, but don't want to directly comment on for any reason (e.g. because you're feeling embarassed, because the post is too old to attract much traffic, etc.). In the spirit of various Stupid Questions threads, you're explicitly encouraged to ask even for the kinds of explanations that you feel you "should" get even yourself, or where you feel like you could get it if you just put in the effort (but then never did).

You can ask to have some specific confusing term or analogy explained, or to get the main content of a post briefly summarized in plain English and without jargon, or anything else. (Of course, there are some posts that simply cannot be explained in non-technical terms, such as the ones in the Quantum Mechanics sequence.) And of course, you're encouraged to provide explanations to others!

ErinFlight said:

I'm struggling to understand anything technical on this website. I've enjoyed reading the sequences, and they have given me a lot to thing about. Still, I've read the introduction to Bayes theorem multiple times, and I simply can't grasp it. Even starting at the very beginning of the sequences I quickly get lost because there are references to programming and cognitive science which I simply do not understand.

I have heard a claim that UDT is a kind of "sane precomputed EDT" (?). Why are "you" (they?) basing UDT on EDT? Is this because you are using the level of abstraction where causality somehow goes away, like it goes away if you look at the universal wave function (???). Maybe I just don't understand UDT? Can you explain UDT? :)

I am trying very very hard to be charitable to the EDT camp, because I am sure there are very smart people in that camp (Savage? Although I think he was aware of confounding issues and tried to rule them out before licensing an action. The trouble is you cannot do it with just conditional independence, that way lie dragons). This is why I keep asking about EDT.

I'll try to explain UDT by dividing it into "simple UDT" and "general UDT". These are some terms I just came up with, and I'll link to my own posts as examples, so please don't take my comment as some kind of official position.

"Simple UDT" assumes that you have a set of possible histories of a decision problem, and you know the locations of all instances of yourself within these histories. It's basically a reformulation of a certain kind of single-player games that are already well known in game theory literature. For more det... (read more)

0[anonymous]12y

It seems to me that talking about EDT, causality and universal wavefunctions is overcomplicating things a little. Let me just describe a problem that could motivate the creation of UDT, and you tell me if it makes sense to you. Consider cellular automata. There's no general concept of causality for CA because some of them are reversible and can be computed in either direction. But you can still build a computer inside a CA and write a program for it. The program will output instructions for some robot arms inside the CA to optimize some utility function on the CA's states. Let's also assume that the initial state of the CA can contain multiple computers running the program, with different architectures etc. A complete description of the initial state will be given to the program at startup, so there's no uncertainty anywhere in the setup. Now the question is, what's the most general way to write such programs, for different cellular automata and utility functions? It seems to me that if you try to answer that question, you'll first stumble on the idea of giving the program a quined description of itself, so it can find instances of itself inside the CA. Then you'll get the idea of using something like "logical consequences" of different possible outputs, because physical consequences aren't available. Then you'll notice that provability in a formal theory is one possible way to formalize "logical consequences", though it has many problems. And eventually you'll come up with a version of UDT which might look something like this, or possibly this if you're more concerned with provable optimality than computability.

28

Explanations for Less Wrong articles that you didn't understand

28

28

28

Explanations for Less Wrong articles that you didn't understand

28

28