Natural science physics contains in itself synthetical judgments a priori, as principles. ... Space then is a necessary representation a priori, which serves for the foundation of all external intuitions.
Upon the solution of this problem, or upon sufficient proof of the impossibility of synthetical knowledge a priori, depends the existence or downfall of metaphysics.
Some of the craftiest scoundrels that ever walked this earth . . . will gravely jot down in diaries the events of every day, and keep a regular debtor and creditor account with heaven, which shall always show a floating balance in their own favour.
All other swindlers upon earth are nothing to the self-swindlers, and with such pretences did I cheat myself. Surely a curious thing. That I should innocently take a bad half-crown of somebody else's manufacture, is reasonable enough; but that I should knowingly reckon the spurious coin of my own make, as good money!