“I’ll teach you differences” King Lear- his Shakiness.
Shakespeare was writing in the time scientific time of taxonomy, where things are compared to one another to create their own classification. So this declaration from Kent to Oswald would be typical of an Earl’s education. This could have given away his disguise, as he was dressed as Caius in A1 S4, and a peasant wouldn’t have been as educated.
The science of taxonomy is rather fascinating, and I think is summed up by common saying;
If it walks like a duck, sounds like a duck, and looks like a duck- it’s a duck
Which of course isn’t always true. It was an early science after all, and with the contemporary philosophy at the time was a sound way of making sense of the world. Of course these days it’s seen as rather flawed, for example;
Elephants are grey and have tails, but not everything that is grey and with a tail is an elephant.
Criticise it a much as much as I like it was the founding principal for the more detailed organisation of biological flora and fauna as science developed with a greater focus on genetics rather than physical similarities. If you want to find out more, here is the Wiki page!