The Thick Rule Is the Thin Rule

In your book, you make a distinction between thick rules and thin rules. Can you talk us through that? Perhaps why don't you give an example of each? Yes. The thick rule is a rule which assumes that it holds in all context. And probably the thinnest rules that we encounter every day are computer algorithms. But even rules which we might think of as quite a ride, for example, the rules of chess often include elements that we would consider to be more psychological than actually a part of the rules of the game.