In this paper, I address the significance of the key notions of coordination, constitution and convention. My aim in so doing is to provide a better understanding of their relation to conventionalism and to evaluate the prospects for a version of the relativized a priori based on a refinement of the notion of coordination. I stress the Kantian roots of all three concepts. Moreover, I argue that the link between the early logical positivist requirement for the uniqueness of coordination and (...) the Kantian account of empirical objectivity provides an interpretive key that sheds light on the alleged incompatibility between constitutive principles and conventionalism. (shrink)