I. the Relation between Positive and Normative Economics

In his admirable book on The Scope and Method of Political Economy John Neville Keynes distinguishes among “a positive science ... a body of systematized knowledge concerning what is; a normative or regulative science...[,] a body of systematized knowledge discussing criteria of what ought to be...[,]an art... [,] a system of rules for the attainment of a given end”; comments that “confusion between them is common and has been the source of many mischievous errors”; and urges the importance of “recognizing a distinct positive science of political economy.”