In some texts, Leibniz argues that the PSR is a conceptual truth that is derivable from the concepts of a sufficient reason and the concept of a requisite (A VI, ii, 483; see also G VII 393, LC L5.18; A VI.iii.133). The concept of a requisite is that of a necessary condition. In this context, Leibniz defines a sufficient reason as a sufficient condition. If something exists, then all of its requisites have been posited. Leibniz then asserts that if all of a things requisites have been posited, t