Abstract

In this article I discuss two fairly recent interpretations of quantum mechanics, both of which allow for the unconventional concept of “relative factµ: Carlo Rovelli’s Relational Quantum Mechanics and the QBist (Quantum Bayesianist) interpretation of Christopher Fuchs and others. On closer inspection, however, these two interpretations turn out to be quite different in their understanding of relations. In short, relational quantum mechanics objectifies (even reifies) relations, whereas QBism understands them as constituting a domain to be objectified. It is shown that there is the same difference between QBism and relational quantum mechanics as there is between the conception of relations in the critical philosophy of Kant and the conception of relations in Leibniz’s monadology or in the modified monadology of pre-critical Kant.