Abstract
The enigmatic few paragraphs around pages 14-15 of Reason, Truth and History that offer the “proof” of our title have probably generated more interpretative reaction than any other short argument in recent philosophy. Their achievement and significance, however, have remained stubbornly controversial. We reckon that, through the settling dust of the debates over the last 35 years, it is now possible to make out the contours of a reasonably clear set of lessons. Stable answers are in prospect to each of the three main issues: Does the proof work? If so, what exactly does it show? And of what, if any, significance, metaphysical or epistemological, is the result? We outline these answers in this paper.