The principle of insufficient reason is one of those philosophic concepts that are highly symptomatic concerning the ultimate presuppositions of the person who accepts them as fundamental. This principle asserts that where we do not have sufficient reason to regard one possible case as more probable than another, we may treat them as equally probable. It has been violently rejected by various logicians, asserted to produce absurdities, and yet has remained persuasively attractive, being accepted, for example, by such an outstanding (...) logician as Dotterer. It may hence be worth while to inquire what the acceptance of this principle implies and what is the source of its persuasiveness. (shrink)