Under the hands of the great utilitarian writers, therefore, political economy is developed into a science of wealth, taking that term in the pecuniary sense, as things amenable to ownership. The course of things in economic life is treated as a sequence of pecuniary events, and economic theory becomes a theory of what should happen in that consummate situation where the permutation of pecuniary magnitudes takes place without disturbance and without retardation. In this consummate situation the pecuniary motive has its perfect work, and guides all the acts of economic man in a guileless, colorless, unswerving quest of the greatest gain at the least sacrifice. Of course, this perfect competitive system, with its untainted "economic man," is a feat of the scientific imagination, and is not intended as a competent expression of fact. It is an expedient of abstract reasoning; and its avowed competency extends only to the abstract principles, the fundamental laws of the science, which hold only so far as the abstraction holds. But, as happens in such cases, having once been accepted and assimilated as real, though perhaps not as actual, it becomes an effective constituent in the inquirer's habits of thought, and goes to shape his knowledge of facts. It comes to serve as a norm of substantiality or legitimacy; and facts in some degree fall under its constraint, as is exemplified by many allegations regarding the "tendency" of things. To this consummation, which Senior speaks of as "the natural state of man,"[35] human development tends by force of the hedonistic character of human nature; and in terms of its approximation to this natural state, therefore, the immature actual situation had best be stated. The pure theory, the "hypothetical science" of Cairnes, "traces the phenomena of the production and distribution of wealth up to their causes, in the principles of human nature and the laws and events--physical, political, and social--of the external world."[36] But since the principles of human nature that give the outcome in men's economic conduct, so far as it touches the production and distribution of wealth, are but the simple and constant sequence of hedonistic cause and effect, the element of human nature may fairly be eliminated from the problem, with great gain in simplicity and expedition. Human nature being eliminated, as being a constant intermediate term, and all institutional features of the situation being also eliminated (as being similar constants under that natural or consummate pecuniary _regime_ with which the pure theory is concerned), the laws of the phenomena of wealth may be formulated in terms of the remaining factors. These factors are the vendible items that men handle in these processes of production and distribution; and economic laws come, therefore, to be expressions of the algebraic relations subsisting between the various elements of wealth and investment,--capital, labor, land, supply and