Welcome to The Nonlinear Library, where we use Text-to-Speech software to convert the best writing from the Rationalist and EA communities into audio. This is: Consequentialism & corrigibility, published by Steven Byrnes on December 14, 2021 on LessWrong.
Background 1: Preferences-over-future-states (a.k.a. consequentialism) vs Preferences-over-trajectories
The post Coherent decisions imply consistent utilities (Eliezer Yudkowsky, 2017) explains how, if an agent has preferences over future states of the world, they should act like a utility-maximizer (with utility function defined over future states of the world). If they don’t act that way, they will be less effective at satisfying their own preferences; they would be “leaving money on the table” by their own reckoning. And there are externally-visible signs of agents being suboptimal in that sense; I'll go over an example in a second.
By contrast, the post Coherence arguments do not entail goal-directed behavior (Rohin Shah, 2018) notes that, if an agent has preferences over trajectories (a.k.a. universe-histories), and acts optimally with respect to those preferences (acts as a utility-maximizer whose utility function is defined over trajectories), then they can display any external behavior whatsoever. In other words, there's no externally-visible behavioral pattern which we can point to and say "That's a sure sign that this agent is behaving suboptimally, with respect to their own preferences.".
For example, the first (Yudkowsky) post mentions a hypothetical person at a restaurant. When they have an onion pizza, they’ll happily pay $0.01 to trade it for a pineapple pizza. When they have a pineapple pizza, they’ll happily pay $0.01 to trade it for a mushroom pizza. When they have a mushroom pizza, they’ll happily pay $0.01 to trade it for a pineapple pizza. The person goes around and around, wasting their money in a self-defeating way (a.k.a. “getting money-pumped”).
That post describes the person as behaving sub-optimally. But if you read carefully, the author sneaks in a critical background assumption: the person in question has preferences about what pizza they wind up eating, and they’re making these decisions based on those preferences. But what if they don’t? What if the person has no preference whatsoever about pizza? What if instead they’re an asshole restaurant customer who derives pure joy from making the waiter run back and forth to the kitchen?! Then we can look at the same behavior, and we wouldn’t describe it as self-defeating “getting money-pumped”, instead we would describe it as the skillful satisfaction of the person’s own preferences! They’re buying cheap entertainment! So that would be an example of preferences-over-trajectories.
To be more concrete, if I’m deciding between two possible courses of action, A and B, “preference over future states” would make the decision based on the state of the world after I finish the course of action—or more centrally, long after I finish the course of action. By contrast, “preference over trajectories” would allow the decision to depend on anything, even including what happens during the course-of-action.
(Strictly speaking, "preferences over trajectories" should be a superset of "preferences over future states", but in this post I'm treating them as exclusive—i.e., when I write "preferences over trajectories" in this post, I'm hiding an implicit ".other than those that could also be described as a preferences over future states".)
Background 2: Corrigibility is a square peg, preferences-over-future-states is a round hole
A “corrigible” AI is an AI for which you can shut it off (or more generally change its goals), and it doesn’t try to stop you. It also doesn’t deactivate its own shutoff switch, and it even fixes the switch if it breaks. Nor does it have preferences in the opposite direction: it doesn’t try to press the switch itself, and it doesn’t try to persuade you to press the switch. (Note: I’m using the te...