This chapter deals with the role belief plays in inquiry. Inquiry begins by belief that there is a problem and is terminated by belief that a solution is found or cannot be found. It is the beliefs that count, not the truth of the matter. The process is subject to some voluntary control but in most applications it is automatic. This function of belief was described long ago by C. S. Peirce, but has since received little attention. It gives speed and economy to inquiry, with some sacrifice of accuracy for speed, and is relevant to the purpose of belief.