 The criticisms of the metaphysical arguments offered in the Transcendental Dialectic do not bring Kant’s discussion to a close. Indeed, in an “Appendix” to the Transcendental Dialectic, Kant returns to the issue of reason’s positive or necessary role. The curious “Appendix” has provoked a great deal of confusion, and not without reason. After all, the entire thrust of the Dialectic seemed to be directed at “critiquing” and curbing pure reason, and undermining its pretense to any real use. Nevertheless, Kant goes on to suggest that the very reason that led us into metaphysical error is also the source of certain necessary ideas and principles, and moreover, that these rational postulations play an essential role in scientific theorizing (A645/B673; A671/B699). Exactly what role they are supposed to play in this regard is less clear.