 Let \(\bL\) be the set of the closed sentences of a first-order logical language \(L\) (finite, for simplicity) and consider \(h, e \in \bL\). Also let \(e\), the evidence statement, be consistent and contain individual constants only (no quantifier), and let \(I(e)\) be the set of all constants occurring (non-vacuously) in \(e\). So, for example, if \(e = Qa \wedge Ra\), then \(I(e) = \{a\}\), and if \(e = Qa \wedge Qb\), then \(I(e) = \{a,b\}\). (The non-vacuity clause is meant to ensure that if sentence \(e\) happens to be, say, \(Qa \wedge Qb \wedge (Rc \vee \neg Rc)\), then \(I(e)\) still is \(\{a, b\}\), for \(e\) does not really state anything non-trivial about the individual denoted by \(c\). See Sprenger 2011a, 241–242.) Hempel’s theory relies on the technical construct of the development of hypothesis \(h\) for evidence \(e\), or the \(e\)-development of \(h\), indicated by \(dev_{e}(h)\). Intuitively, \(dev_{e}(h)\) is all that (and only what) \(h\) says once restricted to the individuals mentioned (non-vacuously) in \(e\), i.e., exactly those denoted by the elements of \(I(e)\).