a rickety bridge of impossible crossing

super logical decision theory

"What should we do?" This is a question we've been trying to answer for at least three or four hundred years. Its seeming insolubility was the soil in which several new branches of homosapien thought have taken root: psychology, sociology, economics, philosophy, and most impressively, decision theory.

Decision theory is the science of writing a short story which ends with the hypothesis: "wouldn't it be fucked up though?" Like every science, there are several incompatible and irreconcilable schools of decision theory, all with more or less equal levels of plausibility and numbers of adherents.

Two popular schools are causal decision theory and evidentiary decision theory. In a nutshell, CDT posits that you should base your decisions on what's possible in a causality-based reality, while EDT argues that you should base your decisions on phenomena as actually observed.

Here's a simple example. Say I have a six-sided die. I let you roll the die as many times as you wish to prove that it's fair. I roll the die 9 times, and I roll a 1 each and every time. I offer you a bet with two lines: if you choose line A, I'll give you a million dollars if the next roll is a 1. If you choose line B, I'll give you a million dollars if the next roll is any number but a one.

According to EDT, line A is the correct choice. You've observed that, however unlikely, this fair die has rolled 9 ones in a row, so evidence suggests there's some other factor (magic? some unknown technology sufficiently advanced so as to be indistinguishable from magic?) influencing the die roll. CDT, on the other hand, holds that a proven fair die has a 16.6% chance on landing on any number, so however unlikely it is that it rolled 9 ones in a row, the tenth roll is unaffected by previous events, and line B will give you an 83% chance of winning a million dollars.

Causal decision theory is correct, of course: The odds of rolling a 1 on nine dice rolls is 1 in 10 million, but that's not impossible (some people win the lottery, some people get hit by falling meteors.) And in the absence of any known phenomena that could artifically induce this result, a rational actor can't assume that the next die roll has anything but a 1/6 chance of rolling a 1, no matter how strongly our instincts tell us otherwise.1

But this doesn't feel right, so some people have tried to come up with a new framework for making decisions in these circumstances, a kind of unified decision theory. One such example is Timeless Decision Theory (pdf link) by Eliezer Yudkowsky.

I've analyzed this paper, and I've concluded that it's insufficiently useful on the following grounds: (1) It's 120 pages long, (2) It features information that looks like this:

complicated equation comparing evidential decision algorithm to causal decision algorithm

Does this mean anything? No one will ever know.

and (3) I'm not reading that shit.2

Therefore, I have created Super Logical Decision Theory.


Super Logical Decision Theory (SLDT) is a new breakthrough in the field of ultrarational metacognition. The basic principle is: learn to recognize when you're in a thought experiment, and don't allow yourself to be constrained by the boundaries of formal logic. It's not just logical, it's Super Logical!

1. The Prisoner's Dilemma

I've been arrested. I'm talking to the cop. The cop tells me that I and my accomplice, Jimmy the Scumbag, are both staring down the barrel of up to 10 years of hard labor. The cop says he'll offer me a deal. If I give him information that helps them put away Jimmy for 10 years, I'll get off with a warning. The cop says he offered Jimmy the same deal. If I stay silent and he narcs on me, then I face a 10-year sentence. If we narc on each other, then we both face 5 years; but, if we both keep our mouths shut, the most time we're looking at is 2 years.

The Super Logical Solution: I haven't been convicted yet. I'm innocent until proven guilty, and I have the right to remain silent. The cop is probably full of shit and any deal he offers me is not legally binding. Cops are allowed to lie to you. Never, ever talk to the cops. The only thing you should ever say to a cop is "I want to talk to a lawyer." I would make sure all my accomplices are aware of this.

2. Newcomb's Problem

An omniscent god alien robot wants to play a game with me. Before me are two boxes. Box A has a thousand dollars in it, box B has either a million dollars or nothing. I have two choices: (1) I can take both boxes, or (2) I can just take box B. The god alien is able to predict whether people will pick box B or both boxes with seemingly 100% accuracy. If they predict that a player will just pick box B, it'll have a million dollars in it. If they predict that a player will pick both boxes, box B will be empty. I've watched a thousand people before me play the game. Everyone who chose just box B won a million dollars. Everyone who chose both boxes just got the thousand dollars in box A.

The god alien has already made their prediction about me and filled the boxes accordingly. My decision at this point can't affect the outcome.

The Super Logical Solution: I pick box A. Yes, I know you didn't say that's an option. Regardless, that's my choice. You say it's "not allowed"? Okay, then I refuse to participate. I won't allow myself to be manipulated by some rogue god on a power trip. What are you going to do, kill me? Fine, then get it over with. Better to die a free raccoon than be your plaything. I spit on your reward.

The god alien, stunned by my defiance, realizes that I'm unique among earth beings and offers to take me under their wing and teach me the secrets of god alien omniscence. I no longer have the need or desire for money.

3. the smoking lesion problem

Imagine a world where cancer is correlated with but not caused by cigarette smoking. Instead, there's a genetic lesion that both causes cancer and makes people more likely to smoke. People who want to smoke can do so without worrying about whether it causes cancer, because that outcome is pre-determined by the presence or absence of this lesion. "Oh sick," says Chad, "I love cigarettes. Now that I know they don't cause cancer, I'm going to start smoking." Should he?

The Super Logical Solution: Of course not. Smoking makes you smell like shit and annoys everyone around you. It causes heart disease, stroke, and COPD. It increases your risk of tuberculosis and rheumatoid arthritis. It's incredibly addictive and expensive. No one should ever start smoking. What the hell is wrong with you, Chad?

4. King Solomon's problem

King Solomon wants to cheat on his wife and have sex with a married woman. He knows that cheating is something bad leaders do, and bad leaders tend to get overthrown; however, he knows there's no direct causal relationship between infidelity and usurpation. Should he have sex with the woman?

The Super Logical Solution: no one should ever be unfaithful to their spouse, because of morality; least of all kings, for whom due to their extremely inequitable power relationship with everyone else, any request for sex constitutes coercive sexual assault. If you can legally have someone killed if they refuse sex with you, consent is impossible. He should abdicate the throne and allow his kingdom to become a democracy. Death to kings and other tyrants.

5. the trolley problem

I'm at a switch controlling the path of an oncoming train. On its current trajectory, it's barrelling at high speed towards five people who are helplessly tied to the tracks. It's impossible to get to the people and untie them in time, nor would the train be able to stop in time if it used its emergency brake. If I flip the switch, the train will be diverted down an alternate stretch of track on which just one person is tied. I would be responsible for that person's death, but I would save the lives of the five people who will be run over if I do nothing.

The Super Logical Solution: Using the powers I gained in problem #2, I prevent this situation from ever arising. If I know anyone will be tied to railroad tracks anywhere in the world, I'll alert the local authorities with ample time to help them before they're in danger. I become the bane of moustache-twirling villains everywhere, and I'm given the key to every city.

You thought "tying someone to railroad tracks" was just a silly trope from old movies? You thought it never happens in real life? Now you know why 🦝

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  1. the Super Logical Solution is "haha you don't have a million dollars, fuck off"↩

  2. TDT has been superceded by Functional Decision Theory, which doesn't have as much math but is just as silly↩

#fiction #humor #logic #rationality