 Salmon wholeheartedly embraced the frequency interpretation, and in particular Reichenbach’s version of it, which embodies a way of making single case probability assignments. The key notion in this regard is that of weight, taken to represent the predictive value of sentences referring to single events. The idea is that the weight assigned to such sentences derives from the probabilities attached to the reference class to which the event in question belongs. The reference class should obey a criterion of homogeneity, namely it should be chosen so as to include as many cases as possible similar to the one under consideration, excluding dissimilar ones. While Reichenbach recommended choosing “the narrowest class for which we have reliable statistics” (Reichenbach 1938: 316) Salmon opted for “the broadest homogeneous reference class”, because