Positive Science: As per the 19th century experts, economics is a positive science. Since it seeks to explain what has actually happened but not what is ought to happen. According to J.M. Keynes, positive science is defined as "A body of systematised knowledge concerning what ought to be and concerned with the ideal as distinguished from the actual."
Normative Science: With contrast to the Positive Science, Normative Science deals with the "what is ought to happen" cases. That is predictions of future economic development with regards to the present conditions are discussed in this science. The postulations on which economic laws, theories or principles are based relate to man and his problems. If we attempt to test and forecast fiscal actions on their basis the subjectivity elements always penetrates. Therefore, the laws of economics are at best propensities.