I think this picture helps explain the clear difference between rules and protocols.
We have one rule that says: everyone can have a piece of the pie as long as their are the same shape and size. As you can see the rule is clear and respects equality on its face.
Here the rule is being correctly enforced as someone got a proper piece of the pie (correct size and shape). However, it has made very difficult for other people to share the pie, thus defeating the whole purpose of the rule and making the result unfair/unjust.
I think protocols could serve the purpose of designing a correct process in order to get the desired result and hence a just outcome. Protocols add context and information on how a rule should be enforced. A rule always creates margin for interpretation and arbitrage. A protocol guides in order to obtain a result.
Conclusions:
It appears that protocols can be narrowly tailored and can be used to produce specific results that cannot be achieved otherwise. This important when drafting rules that affect speech or equality for example.
If a specific result cannot be achieved through a protocol maybe it’s not worth regulating at all. Protocols can be a proxy to avoid obnoxious/useless/costly rules.
The normal way of cutting the pie into pieces is a top-down pattern.
“I cut you choose” is a protocol that works to establish fairness
A p2p protocol that solves pie cutting in a way that solves the weird-piece problem is an open problem. If you say “each person gets to make 1 cut, and the last person to cut is the first person to choose a piece” it might work out if it’s the first person who has made the asshole cut.
A more complex “last person to cut is first person to choose, and also tag the next person to choose” you might have a way to collaboratively punish the gun making the most asshole cut by putting him last.
This would actually be a good game to try out on a circular piece of paper with a ruler and a set of colored pencils. Everybody draws a line. At the end, all the pieces are cut out but the jigsaw is left assembled so everyone can see the logic. Then you go through the choosing game.
Hey I think this is really cool - i wonder what the “iterated dillemma” looks like apart from the one-shot version. I can take a crack at making a digital prototype if it’s not stepping on any toes?