In his fourth edition of Elements of Theoretical Economics (1900), Leon Walras introduced the device of written pledges to eliminate path dependency: sellers of products and services write out commitments to supply certain quantities at suggested prices with no commodities actually produced and supplied until a set of prices is found at which supply and demand are equal simultaneously in every market. This brought about very serious alterations to the character of the book. Unfortunately, these changes resulted in an incomplete, internally contradictory, and occasionally incoherent text. This...