With characteristic incisiveness Georg Henrik von Wright identifies pro­ haireticIogic (i. e. the logic of preference) as the core of a general theory of value concepts. Essentially, this nucleus involves the logical study of acts from the point of view of their preferability. 1 (italics added) Though the term prohairesis is found in Plato, as well as in Aristotle's treatment of the relations of preference, it is von Wright who introduces this word into contemporary analytical philoso­ phy, and succinctly specifies the philosophical dimensions it encompasses. The above emphasis upon the philosophical study of the formalization of preferences is a matter of utmost importance for understanding