… is from page 154 of F.A. Hayek’s profound 1952 book The Counter-Revolution of Science, as this book appears as part of volume 13 (Studies on the Abuse & Decline of Reason, Bruce Caldwell, ed. ) of the Collected Works of F.A. Hayek:
It may indeed prove to be far the most difficult and not the least important task for human reason to comprehend its own limitations.