Wilson: [假若閣下不相信男人都是野獸，那豈非否定了a=c, b=c then a=b 的事實？這問題不應單從代數去理解，嚴格上是一個set function。例如 單數是數字、雙數是數字，但單數不是雙數。

這裡 動物是大union set，而男人跟禽獸是分別兩個不同的sub sets，所以男人不一定等於禽獸。

If you disagree "all men are beasts", aren't you disproving "a=c, b=c then a=b"? This is the set problem.  For example, prime numbers are numbers, even numbers are numbers, but prime numbers are not even numbers.

Here, animal is a union set.  Men and beasts are two different sub sets inside the union set.  Those two sub sets are not necessary equal.  Just like men do not have to be the beasts. ]