Stupid Questions Open Thread Round 4

lukeprog

This is for anyone in the LessWrong community who has made at least some effort to read the sequences and follow along, but is still confused on some point, and is perhaps feeling a bit embarrassed. Here, newbies and not-so-newbies are free to ask very basic but still relevant questions with the understanding that the answers are probably somewhere in the sequences. Similarly, LessWrong tends to presume a rather high threshold for understanding science and technology. Relevant questions in those areas are welcome as well. Anyone who chooses to respond should respectfully guide the questioner to a helpful resource, and questioners should be appropriately grateful. Good faith should be presumed on both sides, unless and until it is shown to be absent. If a questioner is not sure whether a question is relevant, ask it, and also ask if it's relevant.

Ask away!

Previously: round 1, round 2, round 3

From the original thread:

This is for anyone in the LessWrong community who has made at least some effort to read the sequences and follow along, but is still confused on some point, and is perhaps feeling a bit embarrassed. Here, newbies and not-so-newbies are free to ask very basic but still relevant questions with the understanding that the answers are probably somewhere in the sequences. Similarly, LessWrong tends to presume a rather high threshold for understanding science and technology. Relevant questions in those areas are welcome as well. Anyone who chooses to respond should respectfully guide the questioner to a helpful resource, and questioners should be appropriately grateful. Good faith should be presumed on both sides, unless and until it is shown to be absent. If a questioner is not sure whether a question is relevant, ask it, and also ask if it's relevant.

Ask away!

Maybe the easiest way to understand UDT and TDT is:

UDT = EDT without updating on sensory inputs, with "actions" to be understood as logical facts about the agent's outputs
TDT = CDT with "causality" to be understood as Pearl's notion of causality plus additional arrows for logical correlations

Comparing UDT and TDT directly, the main differences seem to be that UDT does not do Bayesian updating on sensory inputs and does not make use of causality. There seems to be general agreement that Bayesian updating on sensory inputs is wrong in a number of situations, but disagreement and/or confusion about whether we need causality. Gary Drescher put it this way:

Plus, if you did have a general math-counterfactual-solving module, why would you relegate it to the logical-dependency-finding subproblem in TDT, and then return to the original factored causal graph? Instead, why not cast the whole problem as a mathematical abstraction, and then directly ask your math-counterfactual-solving module whether, say, (Platonic) C's one-boxing counterfactually entails (Platonic) $1M? (Then do the argmax over the respective math-counterfactual consequences of C's candidate outputs.)

(Eliezer didn't give an answer. ETA: He did answer a related question here.)

I can see what updating on sensory updating does to TDT (causing it to fail counterfactual mugging). But what does it mean to say that TDT makes use of causality and UDT doesn't? Are there any situations where this causes them to give different answers?

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Stupid Questions Open Thread Round 4

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Stupid Questions Open Thread Round 4

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