I’ve enjoyed using Mirror as a bit of public record of my thinking on some things. Actor Protocols” were an important idea for me in 2022, and so I wanted to publish something on the topic before year end. If only for my own sake in seeing a timeline of my own thinking later.

I think this was really my first tweet on the topic. We were trying to figure out Backed v2, and I noticed there are really different categories of protocols in crypto: those that can be used to ratify arbitrary peer to peer agreement and those that have more of a will: guiding and limiting what participants can do.

To the extent a protocol guides or limits its users, it should be to the end of helping users transaction/come to agreements they might not have otherwise. Creating maximally productive Schelling points.

Some examples of what we can say a certain Actor Protocol “wants.”

I think of these protocols as having been endowed by their makers with some ability to observe change and respond to it: an ability to use information that is often already at their disposal.

Around this same time, I happened to pick up a book I had been carrying around for ten years but never read: The Human Use of Human Beings by Norbert Wiener. The subtitle is “Cybernetics and Society.” It is the less technical version of Wiener’s other book: Cybernetics: Or Control and Communication in the Animal and the Machine.

Wiener coined the term “cybernetics” in its modern usage, and by it he is referring to circular causal feedback, or control loops. Such as a person driving a car: the person perceives the road changing, and they turn the wheel, the wheel turns the tires which turn the car and presents a new view to the driver, and the process begins again.

I do not have the book in front of me right now, so I will not try to do it justice, but he is particularly interested in life-imitating automata that could be broadly defined as (1) having some definite task and (2) being “en rapport with the outer world by some sense organ.” For example, an automatic door is supposed to open for humans and does so via a motion detector. A thermostat is supposed to control the temperature in your house by reading the temperature and turning on the heat if it is too cold.

I could not believe my good fortune in waiting ten years to read this book: until this very moment when I had become interested in this topic. What was so interesting to me is the way in which protocols are en rapport with the world, the sense organ: humans give them the information they need! Often this information is baked into the essence of the protocol: Bitcoin adjusts block difficulty by monitoring the time frequency of valid blocks.

And it’s interesting that this computer/human symbiosis is purely in the digital realm: it is not a door opening for humans or a robot doing your dishes: the protocol recruits humans to provide any input info it needs on its own terms.

So, Cybernetics and feedback control loops offer another, and probably better, lens on Actor Protocols. Along the way I found this great piece from 2020. As is usually the case: someone has already said it, and said it better.

Though I think the picture is even broader than what is described in that piece, and perhaps a new phrase like “Actor Protocol” helps convey that. E.g. I would say Uniswap and AMMs are Cybernetic/feedback control loops, but you won’t find them in this article.