"There is happiness--such as could arouse envy in us--only in the air we have breathed, among people we could have talked to, women who could have given themselves to us. In other words, the idea of happiness is indissolubly bound up with the idea of redemption. The same applies to the idea of the past, which is the concern of history. The past carries with it a secret index by which it is referred to redemption. Doesn't a breath of the air that pervaded earlier days caress us as well? In the voices we hear, isn't there an echo of silent ones? Don't the women we court have sisters they no longer recognize? If so, then there is a secret agreement between past generations and the present one. Then our coming was expected on earth. Then, like every generation that preceded us, we have been endowed with a weak messianic power, a power on which the past has a claim. Such a claim cannot be settled cheaply. The historical materialist is aware of this."
-Walter Benjamin, "On the Concept of History"