What is Economics? if you student's economics so must understand the economy meaning. Economic is a study of men as they live and move and think in the ordinary business of life. But it concerns it self chiely with  those motives which effect, most powerfully and most steadly man's coduct in the business part of life. Everyone who is worth anything carries his higher nature with him to business; and there as elsewhere he is influenced by his personal effections, by his conceptions of duty and his reverence for high ideals. The motive is supplied by a definite amount of money : and it is this definite and exact money measurement of the steadiest motives in business life, which has enabled economics for to outrun every other branch of the study of man. Just as the chemist's fine balance has made chemictry more exact than most other physical sciences; so this economist's balance, rough and  imperfect as it is, has made economics more exact than any other branch of social science. But of course economics cannot be compared with the exact physical science: for it deals with the ever changing anf subtle forces of human nature.

There are several other limitations of the measurement of motive by money to be discussed. The first of these arises from the necesessity of taking account of variations in the amount of pleasure, or other satisfication represented by the  same sum money to different persons and under different circumstances.

A shiling may measure a greather pleasure (or other satisfaction) at one time than a another even for the same person; because money may be more plentiful with him, or because his sensibility may vary.