Abstract
Practical reasons, roughly, are reasons to have our desires and goals, and to do what might secure these goals. I argue for the view that lack of freedom to do otherwise undermines the truth of judgments of practical reason. Thus, assuming that determinism expunges alternative possibilities, determinism undercuts the truth of such judgments. I propose, in addition, that if practical reason is associated with various values in a specified way, then determinism precludes such values owing to determinism's imperiling practical reason.