新古典派経済学
The body of theory later termed "neoclassical economics" or "marginalism" formed from about 1870 to 1910. The term "economics" was popularised by such neoclassical economists as Alfred Marshall as a concise synonym for "economic science" and a substitute for the earlier, broader term "political economy" used by Smith. This corresponded to the influence on the subject of mathematical methods used in the natural sciences. Neoclassical economics systematised supply and demand as joint determinants of price and quantity in market equilibrium, affecting both the allocation of output and the distribution of income. It dispensed with the labour theory of value of which Smith was most famously identified with in classical economics, in favour of a marginal utility theory of value on the demand side and a more general theory of costs on the supply side.