Today we have been wonderfully reminded that:
If the latest XKCD cartoon doesn't blow your mind, here's another fun science fact.
We all know that monkeys are quite a diverse group of critters, but you may not realize that what we humans rather arbitrarily choose to call 'monkeys' are actually two distinct groups of animals. Old World monkeys are the monkeys native to Africa and Asia. New World monkeys are native to the Western Hemisphere.
The two groups of primates are only very distantly related to each other.
The unpalatable truth for human beings is that Old World monkeys are closer to us (and chimpanzees, gorillas, and so on) than they are to New World monkeys. A macaque is more closely related to your first-grade teacher than he is to a howler monkey. So the only reason human beings aren't monkeys, scientifically speaking, is an arbitrary naming convention: we're not monkeys because we're not called monkeys.
So that religious nut who insists that if you take science at its word, we're all basically monkeys? He's right. But I'm sure we'll all agree that there are human beings in this world whom we would find it more disagreeable to count as family than the more agreeable sort of monkeys.
(Incidentally, if you really want your mind blown, you could technically say the same for fish. A trout is more closely related to your uncle Frank than it is to a shark. I'll be sure to mention that in my explosive upcoming pamphlet, On the Illogical Arbitrariness of Zoological Nomenclature.)