The idea of ignorance of ignorance is quite unfamiliar. Indeed, scientific culture generally suppresses awareness of ignorance. But ignorance of ignorance was quite well-known from Plato and Socrates onward; it became unpopular in the scientific revolution with Galileo and Descartes. Since then, the triumphalist faith that science would provide the good and the true has put ignorance to one side, and led scientists to the sin of pride in their scientific conquests. The present predicaments require a renewal of an attitude of humility; and for that, the third prophet of the scientific revolution, Francis Bacon, has words that one would do well to heed. © 1993, Sage Publications. All rights reserved.