 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, then it exists. Thus all of a thing’s requisites are a thing’s sufficient reason. The question-begging assumption is that all the necessary conditions for something to exist are jointly sufficient for it to exist. Anybody who denies the PSR will not agree with this assumption and it is clearly not encoded in the definitions of requisite and sufficient reason provided by Leibniz.