Front Page Titles (by Subject) Lecture VI: Of the Place and Purpose of Definition in Political Economy. - The Character and Logical Method of Political Economy
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Lecture VI: Of the Place and Purpose of Definition in Political Economy. - John Elliot Cairnes, The Character and Logical Method of Political Economy 
The Character and Logical Method of Political Economy (London: Macmillan, 1875 2nd ed).
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Of the Place and Purpose of Definition in Political Economy.
§1. The present will be a convenient occasion on which to offer some remarks on the place and purpose of Definition in Political Economy. In it, as in all scientific undertakings comprising in their purview facts and objects of much variety, an arrangement of such facts and objects in classes according to the relations and affinities which, estimated with reference to the ends of the particular inquiry, happen to be most important, forms an indispensable help in the task of investigation; and, the phenomena having been classed, the separate groups need to be marked by distinct names. In these two operations consists the process of defining in positive science. Of the two, it need scarcely be said, the former, classification, is incomparably the more important, as it is also very much the more difficult operation. As has just been intimated, the problem it involves is to arrange the phenomena comprised in the particular investigation according to the relations and affinities most important with reference to the purpose in hand. A difficulty, however, meets us here at the threshold. For, in order to do this, a knowledge of such relations and affinities, and of their comparative importance in the inquiry, is plainly indispensable. But this is just what a student of nature—it matters not what may be the department of inquiry—cannot possibly at the outset of his enterprise possess. What then is to be done? Simply what the circumstances of the case prescribe—adopt some rough provisional arrangement such as, regard being had to the end and purpose of the inquiry, the superficial appearances of things suggest; and then, as in the course of investigation new relations are brought to light and more important distinctions disclose themselves, employ the larger knowledge thus obtained to correct and amend the original draught. These being the necessary conditions under which every new inquiry must be conducted, it follows that classification, except by the merest accident, cannot in the early stages of a positive science, be otherwise than extremely imperfect; and secondly, that the students of such a science must be prepared for the necessity of constantly modifying their classifications and, by consequence, their definitions with the advance of their knowledge, in order to bring them into correspondence with the larger views and more exact ideas which this advance involves; nor can they ever be sure that their arrangements are definitive, so long at least as their science stops short of absolute perfection.
§2. "Nomenclature, in a systematic point of view," says Sir John Herschel, pp. 138, 139, "is as much, perhaps more, a consequence than a cause of extended knowledge. Anyone may give an arbitrary name to a thing, merely to be able to talk of it; but to give a name which shall at once refer it to a place in a system, we must know its properties; and we must have a system, large enough, and regular enough, to receive it in a place which belongs to it, and to no other. It appears, therefore, doubtful whether it is desirable, for the essential purposes of science, that extreme refinement in systematic nomenclature should be insisted on. Were science perfect, indeed, systems of classification might be agreed on, which should assign to every object in nature a place in some class, to which it more remarkably and pre-eminently belonged than to any other, and under which it might acquire a name, never afterwards subject to change. But, so long as this is not the case, and new relations are daily discovered, we must be very cautious how we insist strongly on the establishment and extension of classes which have in them anything artificial, as a basis of a rigid nomenclature; and especially how we mistake the means for the end, and sacrifice convenience and distinctness to a rage for arrangement."
Now all this is quite as applicable to Political Economy as to any physical science. The first inquirers into the laws of the production and distribution of wealth could not know at the outset of their inquiries what arrangement of the facts and objects forming the subject matter of their problem would best conduce towards its solution. They could only therefore adopt that arrangement which was at the moment most promising, and this, previous to the scientific investigation of the phenomena, would naturally be the very classifications which popular discussions on political and social affairs had rendered familiar. But as investigation proceeded, and the more fundamental relations of things under their economical aspect were brought to light, the necessity for new arrangements of the phenomena, and a corresponding modification of economic language, would become apparent; and thus economic terms would come to be employed in senses sometimes narrower, sometimes more extended, than the popular use. It is manifest from this that great elaboration of definitions, at all events in the early stages of investigation, is a mistake. It is not only for the most part labour thrown away, as subsequent inquiry will in all probability furnish reasons for largely modifying the earlier classifications, however carefully drawn up; but, as Sir John Herschel intimates has happened in physical science, it may even act as a positive hindrance to the progress of knowledge by giving an artificial rigidity to nomenclature at a time when it is most important that it should be flexible and elastic. It will accordingly be found that the writers who have done most for Political Economy in its early stages, have troubled themselves but little with definitions. The number of definitions, for example, to be found in the economical writings of Turgot, Adam Smith, and Ricardo, might be counted on the fingers. This, however, is no argument against the gradual introduction of a scientific nomenclature into this science as the progress of our knowledge reveals the necessity of taking note of conditions naturally enough overlooked in the first essays at interpretation. Such a nomenclature serves a double purpose: it becomes a record of the degree of progress actually achieved, and it supplies a frame-work or scaffolding from which the builders may carry up the structure to higher elevations. I say a 'scaffolding,' because it must ever be borne in mind that in Political Economy, as in all the positive sciences, classification, definition, nomenclature, is scaffolding and not foundation,—consequently a part of the work which we must always be prepared to modify or cast aside so soon as it is found to interfere with the progress of the building.
I remarked just now that Ricardo has given few definitions, but undoubtedly he carried the science to a point at which definitions became urgently needed. This want his successors have attempted to supply, not always I think with a just apprehension of what the aim of definition in a progressive science should be. I am far from thinking that Political Economy has yet reached a stage at which a complete nomenclature, a nomenclature making any pretensions to being definitive, could be constructed, or that it would be wise to make the attempt; but perhaps we have attained a point at which some precision may be usefully essayed in giving shape to its more fundamental conceptions. Even here, however, it must be admitted, the science is far yet from having spoken its last word; and consequently even here our definitions must still be taken as provisional only,—as liable to be modified, or it may be entirely set aside as the exigencies of advancing knowledge may prescribe.
§3. In connection with the subject of classification, a further remark must be made. In controversies about definitions nothing is more common than to meet objections founded on the assumption that the attribute on which a definition turns ought to be one which does not admit of degrees. This being assumed, the objector goes on to show that the facts or objects placed within the boundary line of some definition to which exception is taken, cannot in their extreme instances be clearly discriminated from those which lie without. Some equivocal example is then taken, and the framer of the definition is challenged to say in which category it is to be placed. Now, it seems to me that an objection of this kind ignores the inevitable conditions under which a scientific nomenclature is constructed alike in Political Economy and in all the positive sciences. In such sciences nomenclature, and therefore definition, is based upon classification, and to admit of degrees is the character of all natural facts. As has been said, there are no hard lines in nature. Between the animal and vegetable kingdoms, for example, where is the line to be drawn? Vegetables only, it is true, decompose carbonic acid, but then all vegetables (e.g. the fungi, which obtain their carbon by feeding on other vegetables and some parasitic plants) do not do so. Some vegetables have motor-action like animals; and again, the lowest classes of animals have no muscles or nerves. "If, then," says Mr. Murphy, "vegetables have motor-actions like animals, and if there are whole tribes of vegetables which, like animals, do not decompose carbonic acid, and if the lowest class of animals have no muscles or nerves,—what is the distinction between the kingdoms? I reply that I do not believe there is any absolute or certain distinction whatever."56 External objects and events shade off into each other by imperceptible differences; and consequently definitions whose aim it is to classify such objects and events must of necessity be founded on circumstances partaking of this character. The objection proceeds on the assumption that groups exist in nature as clearly discriminated from each other as are the mental ideas formulated by our definitions; so that where a definition is sound the boundary of the definition will have its counterpart in external facts. But this is an illusion. No such clearly cut divisions exist in the actual universe; and if we feign them in our classifications, we should bear in mind that they are after all but fictions—contrivances called for, indeed, and rendered necessary by the weakness of the human intellect, which is unable to contemplate and grasp nature as a whole, but having no counterpart in the reality of things. Let me not, however, be misunderstood. I say our classifications are fictions, but, if sound, they are fictions founded upon fact. The distinctions, formulated in the definition of the class, have a real existence, though the facts or objects lying on each side of the line, and embodying the distinguished attributes, fade into each other by imperceptible degrees. The element of fiction lies, not in the qualities attributed to the things defined, but in the supposition that the objects possessing these qualities are in nature clearly discriminated from those that are without them. It is, therefore, no valid objection to a classification, nor, consequently, to the definition founded upon it, that instances may be found which fall or seem to fall on our lines of demarcation. This is inevitable in the nature of things. But, this notwithstanding, the classification, and therefore the definition is a good one, if in those instances which do not fall on the line, the distinctions marked by the definition are such as it is important to mark, such that the recognition of them will help the inquirer forward towards the desiderated goal.
§4. The other portion of the defining process is naming, which, though less important than classification, is still far from being without serious bearing on the successful cultivation of positive knowledge. On this subject the following weighty aphorism, laid down by Mr. Mill, deserves our consideration:—
"Whenever the nature of the subject permits our reasoning processes to be, without danger, carried on mechanically, the language should be constructed on as mechanical principles as possible; while, in the contrary case, it should be so constructed that there shall be the greatest possible obstacles to a merely mechanical use of it."57
Now within which of the categories here indicated ought Political Economy, regard being had to the nature of its subject, to be considered as falling? Within the category in which our reasoning processes may be carried on mechanically without danger, and in which, therefore, the language should be constructed on as mechanical principles as possible; or within that in which the language should be constructed on the opposite principle of preventing its employment, as far as possible, in a merely mechanical way? I have no hesitation in saying that Political Economy belongs pre-eminently to the group of studies in which the reasoning processes cannot be carried on mechanically without the gravest danger, and in which, consequently, the rule laid down in the latter portion of the aphorism just quoted for the construction of a nomenclature ought to be observed. The subject, has been discussed by Mr. Mill in its widest bearings in his chapter on the requisites of a philosophical language,58 and need not, therefore, be entered into here at any length. But if anyone doubts the soundness of this position, I would ask him to reflect upon the mental processes by which economic truths are established. Let him follow the course of proof in any actual case, and I think he will find that, in order to the right conduct of the ratiocination, by much the most important condition is, that in each step of the argument the reasoner should keep as fully as possible before him the actual concrete circumstances denoted by the terms he employs. I think he will find that it is mainly in proportion as this has been done that economic reasoning has issued in results of any real value; while to the failure to satisfy this condition may be traced no small proportion of the errors which have marked the course of economic research. I hold, therefore, that it is of the utmost importance, not only in Political Economy, but in all social investigation, that the terms of our nomenclature should, as far as possible, serve as constant reminders of the nature of the concrete objects which they are employed to denote; and that for this purpose, to borrow Mr. Mill's language, "as much meaning as possible should be thrown into the formation" of our economic terms, "the aids of derivation and analogy being employed to keep alive a consciousness of all that is signified by them."
It will serve to throw light at once on the resources at the disposal of the economist in this respect, and also on the special difficulties under which Political Economy labours in the matter of definition, if we advert for a moment to the case of the physical science which offers the most perfect example of a nomenclature framed on the principle we have now in view. This is chemistry, in which the nomenclature is at once significant and technical—significant, inasmuch as its terms are composed of elements taken either from existing or from the ancient languages which carry their original meaning into their new occupation; and technical, inasmuch as in their actual form they are only employed as members of a scientific nomenclature. Such words as oxygen, hydrogen, carbonate of lime, peroxide of iron, are all full of meaning, but are never employed except to express certain known chemical elements or combinations. From this union of the two qualities of significance and technicality in its nomenclature an immense advantage results for chemical science; since its terms have in consequence the power of calling up with great distinctness the concrete objects they are intended to denote; while, having been constructed for the special purpose of designating those objects, and never being employed in common speech, they are free from all associations which could confuse or mislead either those who employ or those who hear them. The point, then, to be considered is how far it is possible to construct for Political Economy a nomenclature which shall fulfil the same ends as nomenclature in chemistry. It appears to me that a certain approximation towards this result is feasible, but only an approximation, and that, after all is done, the technical language of Political Economy must ever fall vastly short of the perfection attained by terminology in chemical science. In coming to this conclusion I assume it as settled that the technical terms of Political Economy are to be taken from popular language, and this, not merely as regards their elements, as is done in chemistry, but, so to speak, bodily in their complete forms. Whether it would, at any time, have been possible to have constructed an economic nomenclature on the plan adopted in chemistry is perhaps scarcely worth considering. The science has, in fact, been developed through the instrumentality of popular language. It is through this medium that the ideas of all its greatest thinkers have been put forth; it is in this clothing that the world is familiar with them; and it is, therefore, now palpably too late, even if there were no other restraining consideration, to think of recasting its doctrines in other forms. Such words as production, distribution, exchange, value, cost, labour, abstinence, capital, profit, interest, wages, must now for good or for evil remain portions of economic nomenclature; and these have all been drawn in their actual forms from the vernacular, and are in constant use in popular speech. With regard to such words they are capable enough of fulfilling the first of the two functions fulfilled by nomenclature in chemistry—of calling up, that is to say—always supposing them to be used with deliberation—concrete facts and objects with sufficient vividness. The hitch occurs in their inaptitude for the second of the two purposes required of them, for bringing to the mind the exact facts and objects, neither more nor fewer, which we desire to indicate.
For the position of things is this:—The economist finds it necessary, for the reasons which have been stated above, to arrange the phenomena of wealth in classes on a certain principle—that principle being in fact the convenience of his own investigations; and he has to find names for the classes thus constituted in the terms of popular language. But popular language has not been framed to suit the convenience of economic speculation, but with quite other views. Its distinctions and classifications do not always or generally coincide with those which are most important for the elucidation of the economy of wealth; and even where this correspondence is tolerably close, a term in constant use in ordinary speech inevitably gathers round it a vague aroma of association, sure to suggest in particular contexts ideas which have no proper connection with the purposes of scientific research, and which therefore cannot but act as hindrances to the reasoning process. That precision of meaning, accordingly, which is so conspicuous in the nomenclature of chemistry, and in general of the physical sciences, is unattainable in Political Economy. Its nomenclature satisfies indeed the condition of having plenty of meaning. With even greater vividness than the nomenclature of chemistry it is capable of calling up the concrete things denoted by its terms; but for this advantage it pays the heavy price of loss of precision—of vagueness and uncertainty as to the proper limitation to be given to its most important words. The remedy, so far as remedy is possible, seems to be twofold:—first, to keep our definitions of economic terms as close to the usages of common speech as the requirements of correct classification will allow. Terms must indeed, now and then, be strained to express meanings and to suffer limitations which in ordinary discourse they do not express or bear, since otherwise the ends of classification would be sacrificed; and it is, therefore, no conclusive objection to an economic definition that it does not accurately coincide with popular use. But it should, nevertheless, be fully recognised that such deviations constitute a demerit in definition, and may become a serious one. The second remedy against the evil is clearness and distinctness of definition wherever terms of importance are employed; care being taken, where the economic sense differs from the popular one, to bring into as strong relief as possible the points of difference; with which precaution the practice may be usefully combined of throwing in a caveat from time to time, where the context would be in danger of suggesting the popular rather than the scientific sense.
§5. We may now sum up the general results of the foregoing discussion:—
1. The first requisite of a good definition in Political Economy is that it should mark those distinctions in facts and objects which it is important to mark with a view to the elucidation of the phenomena of wealth; and our nomenclature will be good or bad, helpful or obstructive, according as it coincides with such real and pertinent distinctions, or sets up others which are arbitrary, fanciful, or irrelevant.
2. So far as is consistent with satisfying the foregoing condition, economic terms should be used as nearly as possible in their popular sense; though, as strict adherence to popular usage is not compatible with fulfilling the requirements of sound classification, the mere circumstance of deviation from popular usage is no conclusive objection to an economic definition.
3. It is no valid objection to an economic definition that the attribute on which it turns is found to exhibit degrees in its concrete embodiments. This is inevitable from the nature of the case.
4. Definitions in the present state of economic science should be regarded as provisional only, and may be expected to need constant revision and modification with the progress of economic knowledge. Economic definitions are thus progressive. A complete nomenclature pretending to be definitive would at present be premature, and, if framed and generally accepted, would probably prove obstructive. But the time has come when increased precision may be usefully given to the more fundamental conceptions, always with the understanding that these also must still be taken as provisional.
[56.] 'Habit and Intelligence,' by J. J. Murphy. Vol. i., p. 165.
[57.] 'Logic.' Book IV., chap. vi., § 6.
[58.] 'Logic.' Book IV., chap. vi.