Friedrich Nietzsche on Sui generis

“According to the extent to which a spirit is sui generis, the limits of what is permitted—that is, beneficial to him—become more and more narrow.”

“In the human race, also, the superior specimens, the happy cases of evolution, are the first to perish amid the fluctuations of chances. ... The short duration of beauty, of genius, of the Caesar, is sui generis: such things are not hereditary. The type is inherited, there is nothing extreme or particularly "happy" about a type. ... The higher type is an example of an incomparably greater degree of complexity—a greater sum of co-ordinated elements: but on this account disintegration becomes a thousand times more threatening. "Genius" is the sublimest machine in existence—hence it is the most fragile.”