The question of universalism and relativism is often taken to be a matter of critical reflexivity. This article attempts to present the question instead as a matter of practical, political, and always-situated concern. The attempt starts from the consideration of modern experimental sciences. These sciences usually serve as the stronghold for universalist claims and as such are a target of relativism. It is argued that the specificity of these sciences is not a method but a concern. To be able to claim that they have not unilaterally imposed their definitions on the phenomena they study is the leading concern of experimenters and should be understood in terms of the following achievement: the creation of a very particular “rapport” that authorizes claiming that what is operationally defined “lends itself” to this correlation. Linking knowledge production with a creation of rapports entails a pluralization of sciences along with the pluralization of modes of concern associated with the rapport. However, resisting unilaterally imposed definitions is not enough, since with the coming “knowledge economy” the questions that this article raises will soon be part of a romantic past. Thus it concludes with a speculative touch, which may be a requiem, relating the creation of rapports with an ecology of practices akin to William James's always-under-construction pluriverse.