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Calculus in Game and Decision Theory
Intuitive Introduction to Functional Decision Theory
Critiques of FDT Often Stem From Confusion About Newcomblike Problems
Heighn23d10

Why do you believe this is a scenario in which you are definitely not in a simulation?

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What are the two contradictory theories of how to evaluate counterfactuals?
Heighn26d30

Yeah, it matches wat @mesaoptimizer said, I believe. I was reluctant to post my view, but thought it could be helpful anyway :)

Great question! I'm wondering the same thing now. I, for one, had to be reasoned into it. It does feel like it "clicked", so to speak, but I doubt whether anyone has this intuition naturally.

I would be willing to discuss FDT more, if you'd like (in a separate post, of course).

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What are the two contradictory theories of how to evaluate counterfactuals?
Answer by HeighnAug 21, 202530

Regarding (2), I interpret Soares' point as follows: there's a "CDT intuition" and an "FDT intuition" of how to evaluate counterfactuals. Let's just take the Bomb problem as an example.

CDT intuition

The CDT intuition deals with which action has the best causal consequences at one given point in time. In Bomb, you can either Left-box or Right-box. There's a bomb in Left, so Left-boxing causes you to die painfully. Right-boxing costs only $100, so right-boxing wins.

FDT intuition

The FDT intuition deals with which decision is the best outcome of your decision procedure. Your decision procedure is a function, and could be implemented more than once. In Bomb, it's implemented both in your head and in the predictor's head (she executed it to predict what you would do). Your decision to Left-box or to Right-box therefore happens twice - and, since your decision procedure is a function, it's necessarily the same on both events - and you have to look at the causal consequences of both events. Left-boxing causes the predictor to not put a bomb in Left and you to not lose $100, while Right-boxing causes the predictor to put a bomb in Left and you to lose $100. Left-boxing wins.

P.S. A natural thing to respond here is something like: "But you already see a Bomb in Left, so the FDT intuition makes no sense!" But note that, since the predictor simulates you in order to make her prediction, you don't actually know whether you are the "real you" or the "simulated you", since the simulated you observes the exact same (relevant) things as the real you. (If not, then the simulation would not be accurate and there would be no subjunctive dependence.) So in this intuition, observing the bomb does not actually mean there is a bomb, since you could be in a simulation. In fact, you are, at different points in time, both in the simulation and in the "real" situation, and you have to make a decision that happens in and makes the best of both these situations.

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Found Paper: "FDT in an evolutionary environment"
Heighn2y40

"In your problem description you said you receive the letter"

True, but the problem description also specifies subjunctive dependence between the agent and the predictor. When the predictor made her prediction the letter isn't yet sent. So the agent's decision influences whether or not she gets the letter.

"This intuition is actually false for perfect predictors."

I agree (and have written extensively on the subject). But it's the prediction the agent influences, not the presence of the termite infestation.

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Found Paper: "FDT in an evolutionary environment"
Heighn2y10

Given that you receive the letter, paying is indeed evidence for not having termites and winning $999,000. EDT is elegant, but still can't be correct in my view. I wish it were, and have attempted to "fix" it.

My take is this. Either you have the termite infestation, or you don't.

Say you do. Then

  • being a "payer" means you never receive the letter, as both conditions are false. As you don't receive the letter, you don't actually pay, and lose the $1,000,000 in damages.
  • being a "non-payer" means you get the letter, and you don't pay. You lose $1,000,000.

Say you don't. Then

  • payer: you get the letter, pay $1,000. You lose $1,000.
  • non-payer: you don't get the letter, and don't pay $1,000. You lose nothing.

Being a payer has the same result when you do have the termites, but is worse when you don't. So overall, it's worse. Being a payer or a non-payer only influences whether or not you get the letter, and this view is more coherent with the intuition that you can't possibly influence whether or not you have a termite infestation.

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Found Paper: "FDT in an evolutionary environment"
Heighn2y11-2

XOR Blackmail is (in my view) perhaps the clearest counterexample to EDT:

An agent has been alerted to a rumor that her house has a terrible termite infestation that would cost her $1,000,000 in damages. She doesn’t know whether this rumor is true. A greedy predictor with a strong reputation for honesty learns whether or not it’s true, and drafts a letter:

 I know whether or not you have termites, and I have sent you this letter iff exactly one of the following is true: (i) the rumor is false, and you are going to pay me $1,000 upon receiving this letter; or (ii) the rumor is true, and you will not pay me upon receiving this letter.

The predictor then predicts what the agent would do upon receiving the letter, and sends the agent the letter iff exactly one of (i) or (ii) is true. Thus, the claim made by the letter is true. Assume the agent receives the letter. Should she pay up?

(Styling mine, not original.) EDT pays the $1,000 for nothing: it has absolutely no influence on whether or not the agent's house is infested with termites.

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Job listing: Communications Generalist / Project Manager
Heighn2y10

Alright, thanks for your answer!

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Job listing: Communications Generalist / Project Manager
Heighn2y10

Is it necessary to be able to work during all MIRI office hours, or is it enough if my hours are partially compatible? My time difference with MIRI is 9 hours, but I could work in the evening (my time) every now and then.

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Load More
7Critiques of FDT Often Stem From Confusion About Newcomblike Problems
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4The omnizoid - Heighn FDT Debate #5
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6The omnizoid - Heighn FDT Debate #3: Contra omnizoid contra me contra omnizoid contra FDT
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24The omnizoid - Heighn FDT Debate #1: Why FDT Isn't Crazy
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3Is AI Alignment Impossible?
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3The Calculus of Newcomb's Problem
3y
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5The Calculus of Nash Equilibria
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3A Very Mathematical Explanation of Derivatives
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6No, EDT Did Not Get It Right All Along: Why the Coin Flip Creation Problem Is Irrelevant
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19An Intuitive Introduction to Functional Decision Theory
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Causal Decision Theory
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Functional Decision Theory
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