“I’ll teach you differences.”

Wittgenstein suggested an epigraph for Philosophical Investigations could be a line from King Lear: “I’ll teach you differences.”

Elsewhere, he writes:

The older I grow the more I realize how terribly difficult it is for people to understand each other, and I think that what misleads one is the fact that they all look so much like each other. If some people looked like elephants and others like cats, or fish, one wouldn’t expect them to understand each other and things would look much more like what they really are. 

Source.