By the great pessimist.
He writes in one of his essays
That human life must be a kind of mistake is sufficiently clear from the fact that man is a compound of needs, which are difficult to satisfy; moreover, if they are satisfied, all he is granted is a state of painlessness, in which he can only give himself up to boredom. This is a precise proof that existence in itself has no value, since boredom is merely the feeling of the emptiness of life.
If life had in itself any positive and real value, boredom could not exist, mere existence in itself would supply us with everything and therefore satisfy us.