Diospyros kaki Thunb. / Diospyros lotus L.
«The word man is, in like manner, a sign to denote the general notion of what all men have in common, and it would be very difficult to tell, or to make the enumeration of, all that this notion contains. Would you say that he is a living two-legged being? A cock would, likewise, be included in this description. Would you say, in the words of Plato's definition, that he is a two-legged animal without feathers? You have only to strip the cock of his feathers in order to obtain the Platonic man.
I do not know whether those who say that man is an animal endowed with reason express themselves more accurately: for, how often do we take for men certain beings of whose rationality we have no assurance. On viewing an army, I have not the least doubt that every soldier is a man, though I have not the smallest proof that they are all endowed with reason.»
Leonhard Euler, Letters to a German princess, Thoemmes Press (1997)