What nostalgia is ordinarily taken to mean
To address [the nostalgia] question—likely to be raised about any account critical of the modern project—one should probably begin by clarifying what nostalgia is ordinarily taken to mean, and what its conceptual premises are. The longing for a past plenitude, as indeed the supposition that it had once existed, rests on two closely related assumptions: first, that historical time is linear rather than cyclical, monochrome in its forward motion rather than recursive and imbued with various kinds of “higher time” or spikes of semantic intensity. For it is this premise that sanctions the axiom of “loss” without which there could not be any nostalgic affect. Second, nostalgia implies that our relationship to the past is one of disaffection, even terminal estrangement, a premise borne out by the self-certifying affect of “longing” at the heart of nostalgia. Yet precisely these premises also show nostalgia to be a distinctively modern phenomenon inasmuch as it acquiesces in the modern (historicist) view of time as a monochrome vector pointing toward the future, which renders the past as strictly passé, that is, as sheer inventory to be, perhaps, objectively known but most definitely incapable of signifying for (let alone transforming) us.
Thomas Pfau, Minding the Modern, as quoted in Matthew Milliner’s excellent review.