Simone De Beauvoir said this quote

“ The continuous work of our life,” says Montaigne, “is to build death.” He quotes the Latin poets: Prima, quae vitam dedit, hora corpsit. And again: Nascentes morimur. Man knows and thinks this tragic ambivalence which the animal and the plant merely undergo. A new paradox is thereby introduced into his destiny. “Rational animal,” “thinking reed,” he escapes from his natural condition without, however, freeing himself from it. He is still a part of this world of which he is a consciousness. He asserts himself as a pure internality against which no external power can take hold, and he also experiences himself as a thing crushed by the dark weight of other things. At every moment he can grasp the non-temporal truth of his existence. But between the past which no longer is and the future which is not yet, this moment when he exists is nothing. This privilege, which he alone possesses, of being a sovereign and unique subject amidst a universe of objects, is what he shares with all his fellow-men. In turn an object for others, he is nothing more than an individual in the collectivity on which he depends. ”