He argued that economics, on one side, is a study of wealth and, on the other, is a study of man.This question is based on Alfred Marshall’s definition of economics as below: Marshall defines economics as “a study of men as they live and move and think in the ordinary business of life.” He argued that economics, on one side, is a study of wealth and, on the other, is a study of man. Welfare definition of economics. The welfare definition of economics is an attempt by Alfred Marshall, a pioneer neoclassical economist, to redefine his field of study. Hence we can say that pioneer of welfare is Alfred Marshall.