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: «Boundaries», Part 1: a key missing concept from utility theory, published by Andrew Critch on July 26, 2022 on The AI Alignment Forum.
This post has been recorded as part of the LessWrong Curated Podcast, and can be listened to on Spotify, Apple Podcasts, and Libsyn.
This is Part 1 of my «Boundaries» Sequence on LessWrong.
Summary: «Boundaries» are a missing concept from the axioms of game theory and bargaining theory, which might help pin down certain features of multi-agent rationality (this post), and have broader implications for effective altruism discourse and x-risk (future posts).
1. Boundaries (of living systems)
Epistemic status: me describing what I mean.
With the exception of some relatively recent and isolated pockets of research on embedded agency (e.g., Orseau & Ring, 2012; Garrabrant & Demsky, 2018), most attempts at formal descriptions of living rational agents — especially utility-theoretic descriptions — are missing the idea that living systems require and maintain boundaries.
When I say boundary, I don't just mean an arbitrary constraint or social norm. I mean something that could also be called a membrane in a generalized sense, i.e., a layer of stuff-of-some-kind that physically or cognitively separates a living system from its environment, that 'carves reality at the joints' in a way that isn't an entirely subjective judgement of the living system itself. Here are some examples that I hope will convey my meaning:
a cell membrane (separates the inside of a cell from the outside);
a person's skin (separates the inside of their body from the outside);
a fence around a family's yard (separates the family's place of living-together from neighbors and others);
a digital firewall around a local area network (separates the LAN and its users from the rest of the internet);
a sustained disassociation of social groups (separates the two groups from each other)
a national border (separates a state from neighboring states or international waters).
Figure 1: Cell membranes, skin, fences, firewalls, group divisions, and state borders as living system boundaries.
Comparison to Cartesian Boundaries.
For those who'd like a comparison to 'Cartesian boundaries', as in Scott Garrabrant's Cartesian Frames work, I think what I mean here is almost exactly the same concept. The main differences are these:
(life-focus) I want to focus on boundaries of things that might naturally be called "living systems" but that might not broadly be considered "agents", such as a human being that isn't behaving very agentically, or a country whose government is in a state of internal disagreement. (I thought of entitling this sequence "membranes" instead, but stuck with 'boundaries' because of the social norm connotation.)
(flexibility-focus) Also, the theory of Cartesian Frames assumes a fixed cartesian boundary for the agent, rather than modeling the boundary as potentially flexible, pliable, or permeable over time (although it could be extended to model that).
Comparison to social norms.
Certain social norms exist to maintain separations between livings systems. For instance:
Personal space boundaries. Consider a person Alex who wants to give his boss a hug, in a culture with a norm against touching others without their consent. In that case, the boss's personal space creates a kind of boundary separating the boss from Alex, and there's a protocol — asking permission — that Alex is expected to follow before crossing the boundary.
Information boundaries for groups. Consider a person Betty who's having a very satisfying romantic relationship, in a culture where there's a norm of not discussing romantic relationships with colleagues at work. In that case, Alice maintains an information barrier between the details of her romantic life and her workplace. The workplace is kind of living...