Objective probabilities, quantum counterfactuals, and the ABL rule - A response to R. E. Kastner

The ABL rule is derived as a tool of standard quantum mechanics. The ontological significance of the existence of objective probabilities is discussed. Objections by Kastner [Am. J. Phys. 69, 860-863 (2001)] and others to counterfactual uses of the ABL rule are refuted. Metaphysical presumptions leading to such views as Kastner is defending in her Comment are examined and shown to be unwarranted. (C) 2001 American Association of Physics Teachers.