Comment on Mohrhoff ’ s “ What quantum mechanics is trying to tell us ”

Mohrhoff's use of the Aharonov-Bergmann-Lebowitz (ABL) rule for time-symmetric objective probabilities, as related to counterfactual intervening measurements between pre-and post-selection, is problematic. The ABL rule was formulated on the assumption that such intervening measurements are actually made, and would therefore correspond to what Mohrhoff is calling " subjective " probabilities. Ulrich Mohrhoff (1999) makes an interesting distinction between " subjective " and " objective " probabilities in quantum mechanics. However, his discussion of the Aharonov-Bergmann-Lebowitz (" ABL ") rule (ABL 1964) as related to counterfactual statements about possible intervening measurements between pre-and post-selection should take into account that there have been numerous objections in the literature to the counterfactual The ABL rule was formulated on the assumption that such intervening measurements are actually made, and would therefore appear to correspond to what Mohrhoff is calling " subjective " probabilities. However, he wishes to