To his harshest critics, Kant's philosophy can seem an unending series of neglected alternatives. Time and again, Kant argues for his position by elimination, ruling out each possible alternative, until his own is the only one left standing. Of course, this strategy amounts to a demonstration of the Kantian position if and only if the field of possible alternatives really is – as Kant always assumes – exhaustive. But readers often suspect that Kant has stacked the deck, that his dogmatic adherence to a particular set of presuppositions, or perhaps simply his lack of philosophical imagination, has unjustifiably restricted the possibilities under consideration, thereby rendering the alleged argument by elimination nothing but an elaborate exercise in question begging.