more from Saul A. Kripke

Single Idea 19269

[catalogued under 18. Thought / A. Modes of Thought / 10. Rule Following]

Full Idea

I will define 'quus' by x-quus-y = x + y, if x, y < 57, and otherwise it equals 5. Who is to say that this is not the function I previously meant by '+'?

Gist of Idea

'Quus' means the same as 'plus' if the ingredients are less than 57; otherwise it just produces 5


Saul A. Kripke (Wittgenstein on Rules and Private Language [1982], 2)

Book Reference

Kripke,Saul: 'Wittgenstein on Rules and Private Language' [Blackwell 1993], p.9

A Reaction

Kripke's famous example, to illustrate the big new scepticism introduced by Wittgenstein's questions about the rationality of following a rule. I suspect that you have to delve into psychology to understand rule-following, rather than logic.