Essays on some unsettled Questions of Political Economy

by John Stuart Mill

ESSAY V.

ON THE DEFINITION OF POLITICAL ECONOMY; AND ON THE METHOD OF INVESTIGATION PROPER TO IT.

It might be imagined, on a superficial view of the nature and objects of definition, that the definition of a science would occupy the same place in the chronological which it commonly does in the didactic order. As a treatise on any science usually commences with an attempt to express, in a brief formula, what the science is, and wherein it differs from other sciences, so, it might be supposed, did the framing of such a formula naturally precede the successful cultivation of the science.

This, however, is far from having been the case. The definition of a science has almost invariably not preceded, but followed, the creation of the science itself. Like the wall of a city, it has usually been erected, not to be a receptacle for such edifices as might afterwards spring up, but to circumscribe an aggregation already in existence. Mankind did not measure out the ground for intellectual cultivation before they began to plant it; they did not divide the field of human investigation into regular compartments first, and then begin to collect truths for the purpose of being therein deposited; they proceeded in a less systematic manner. As discoveries were gathered in, either one by one, or in groups resulting from the continued prosecution of some uniform course of inquiry, the truths which were successively brought into store cohered and became agglomerated according to their individual affinities. Without any intentional classification, the facts classed themselves. They became associated in the mind, according to their general and obvious resemblances; and the aggregates thus formed, having to be frequently spoken of as aggregates, came to be denoted by a common name. Any body of truths which had thus acquired a collective denomination, was called a science. It was long before this fortuitous classification was felt not to be sufficiently precise. It was in a more advanced stage of the progress of knowledge that mankind became sensible of the advantage of ascertaining whether the facts which they had thus grouped together were distinguished from all other facts by any common properties, and what these were. The first attempts to answer this question were commonly very unskilful, and the consequent definitions extremely imperfect.

And, in truth, there is scarcely any investigation in the whole body of a science requiring so high a degree of analysis and abstraction, as the inquiry, what the science itself is; in other words, what are the properties common to all the truths composing it, and distinguishing them from all other truths. Many persons, accordingly, who are profoundly conversant with the details of a science, would be very much at a loss to supply such a definition of the science itself as should not be liable to well-grounded logical objections. From this remark, we cannot except the authors of elementary scientific treatises. The definitions which those works furnish of the sciences, for the most part either do not fit them—some being too wide, some too narrow—or do not go deep enough into them, but define a science by its accidents, not its essentials; by some one of its properties which may, indeed, serve the purpose of a distinguishing mark, but which is of too little importance to have ever of itself led mankind to give the science a name and rank as a separate object of study.

The definition of a science must, indeed, be placed among that class of truths which Dugald Stewart had in view, when he observed that the first principles of all sciences belong to the philosophy of the human mind. The observation is just; and the first principles of all sciences, including the definitions of them, have consequently participated hitherto in the vagueness and uncertainty which has pervaded that most difficult and unsettled of all branches of knowledge. If we open any book, even of mathematics or natural philosophy, it is impossible not to be struck with the mistiness of what we find represented as preliminary and fundamental notions, and the very insufficient manner in which the propositions which are palmed upon us as first principles seem to be made out, contrasted with the lucidity of the explanations and the conclusiveness of the proofs as soon as the writer enters upon the details of his subject. Whence comes this anomaly? Why is the admitted certainty of the results of those sciences in no way prejudiced by the want of solidity in their premises? How happens it that a firm superstructure has been erected upon an unstable foundation? The solution of the paradox is, that what are called first principles, are, in truth, last principles. Instead of being the fixed point from whence the chain of proof which supports all the rest of the science hangs suspended, they are themselves the remotest link of the chain. Though presented as if all other truths were to be deduced from them, they are the truths which are last arrived at; the result of the last stage of generalization, or of the last and subtlest process of analysis, to which the particular truths of the science can be subjected; those particular truths having previously been ascertained by the evidence proper to their own nature.

Like other sciences, Political Economy has remained destitute of a definition framed on strictly logical principles, or even of, what is more easily to be had, a definition exactly co-extensive with the thing defined. This has not, perhaps, caused the real bounds of the science to be, in this country at least, practically mistaken or overpassed; but it has occasioned—perhaps we should rather say it is connected with—indefinite, and often erroneous, conceptions of the mode in which the science should be studied.

We proceed to verify these assertions by an examination of the most generally received definitions of the science.

1. First, as to the vulgar notion of the nature and object of Political Economy, we shall not be wide of the mark if we state it to be something to this effect:—That Political Economy is a science which teaches, or professes to teach, in what manner a nation may be made rich. This notion of what constitutes the science, is in some degree countenanced by the title and arrangement which Adam Smith gave to his invaluable work. A systematic treatise on Political Economy, he chose to call an Inquiry into the Nature and Causes of the Wealth of Nations; and the topics are introduced in an order suitable to that view of the purpose of his book.

With respect to the definition in question, if definition it can be called which is not found in any set form of words, but left to be arrived at by a process of abstraction from a hundred current modes of speaking on the subject; it seems liable to the conclusive objection, that it confounds the essentially distinct, though closely connected, ideas of science and art. These two ideas differ from one another as the understanding differs from the will, or as the indicative mood in grammar differs from the imperative. The one deals in facts, the other in precepts. Science is a collection of truths; art, a body of rules, or directions for conduct. The language of science is, This is, or, This is not; This does, or does not, happen. The language of art is, Do this; Avoid that. Science takes cognizance of a phenomenon, and endeavours to discover its law; art proposes to itself an end, and looks out for means to effect it.