Any kind of general behavior is likely in accordance with a rule. For instance, I can turn collections of written signs into sounds because I know the rule provided by the alphabet for converting written signs into sounds. There is no limit to how high I can count because I know the rule according to which successive numbers are generated. In this respect, all our behavior beyond individual, isolated actions, involves rule following. Wittgenstein was the first thinker to recognize the philosophical signif icance of this idea.

I can turn written signs into sounds because I know the rule of the alphabet. But how do I know how to follow the rule of the alphabet? For instance, if there is a table corresponding each letter to a sound, how do I know how to read that table? We need a further rule on how to read tables. And then we likely need another rule to interpret that second rule.

Wittgenstein shows us that there is nothing about rules in themselves that justify our general behavior. We cannot simply point to a rule as an explanation, because that rule needs justification just as the initial general behavior does. Wittgenstein conc ludes that there is no ultimate justification for our behavior.