This book concerns the first half of Kant's Critique of Pure Reason; a treatment of the second half, under the title Kant's Dialectic, is in preparation. The present work ought to be readable by those who know nothing of the Critique. It is in some sense an ‘introduction’, but a selective one which does not expound all the Critique's most important themes. What I hope it provides is one fairly unified way of viewing a good part of Kant's achievement.

To this end I have freely criticized, clarified, interpolated and revised. I make no apology for adopting this approach, for fighting Kant tooth and nail. Had I instead indulged him, or even given him the benefit of every doubt, I could neither have learned from his opaque masterpiece nor reported intelligibly on what it says.

Like all great pioneering works in philosophy, the Critique is full of mistakes and confusions. It is a misunderstanding to think that a supreme philosopher cannot have erred badly and often: the Critique still has much to teach us, but it is wrong on nearly every page.

I have no feelings about the man Immanuel Kant; and in my exploration of his work I have no room for notions like those of charity, sympathy, deference, or hostility.

Because I aim to be clear yet fairly brief, I devote little space to acknowledging debts and pursuing disagreements with previous writers on the Critique. I am indeed somewhat out of sympathy with such of these as I have read; but I have learned from the works of Bird, Ewing, Kemp Smith, Körner, Walsh, Weldon and Wolff, more than my comparative silence about them might suggest.

I have, with difficulty, checked Kemp Smith's translation of every passage quoted from the Critique. I do not italicize the phrases ‘a priori’ and ‘a posteriori’; my few other departures from Kemp Smith are noted as they occur.

Following standard practice, I refer to the first edition of the Critique as ‘A’ and the second as ‘B’.

The present work was written in three large Parts and then, early in the re-writing, divided into fifty-four sections.