our conceptions; but this will be the case then only when we have under our consideration some proposition in which the term is employed. For then the question really is, how the conception shall be understood and defined in order that the proposition may be true. concerning the laws of falling bodies | be a useful step in the explication of led to the question whether the proper definition of a uniform force is that it generates a velocity proportional to the space from rest, or to the time. The controversy of the vis viva was what was the proper definition of the measure of force. A principal question in the classification of minerals is, what is the definition of a mineral species? Physiologists have endeavoured to throw light on their subject by defining organisation, or some similar term. Questions of the same nature were long open, and are not yet completely closed, respecting the definitions of Specific Heat, Latent Heat, Chemical Combination, and Solution. was "To unfold our conceptions by means of definitions has never been serviceable to science, except when it has been associated with an immediate use of the definitions. The endeavour to define a Uniform Force was combined with the assertion that gravity is a uniform force: the attempt to define Accelerating Force immediately followed by the doctrine that accelerating forces may be compounded: the process of defining Momentum was connected with the principle that momenta gained and lost are equal: naturalists would have given in vain the definition of Species which we have quoted, if they had not also given the characters of species so separated. Definition may be the best mode of explaining our conception, but that which alone makes it worth while to explain it in any mode, is the opportunity of using it in the expression of truth. When a definition is propounded to us as a useful step in knowledge, we are always entitled to ask what principle it serves to enunciate." "It is very important for us to observe, that these controversies have never been questions of insulated and arbitrary definitions, as men seem often tempted to imagine them to have been. In all cases there is a tacit assumption of some proposition which is to be expressed by means of the definition, and which gives it its importance. The dispute concerning the definition thus acquires a real value, and becomes a question concerning true and false. Thus in the discussion of the question, What is a uniform force? it was taken for granted that gravity is a uniform force. In the debate of the vis viva, it was assumed that in the mutual action of bodies the whole effect of In giving, then, an exact connotathe force is unchanged. In the zoo- tion to the phrase, "a uniform force," logical definition of species, (that it the condition was understood that consists of individuals which have, or the phrase should continue to denote may have, sprung from the same gravity. The discussion, therefore, parents,) it is presumed that indivi- respecting the definition resolved duals so related resemble each other itself into this question, What is there more than those which are excluded of an uniform nature in the motions by such a definition; or, perhaps, produced by gravity? By observathat species so defined have per- tions and comparisons it was found, manent and definite differences. A that what was uniform in those modefinition of crganisation, or of some tions was the ratio of the velocity other term, which was not employed acquired to the time elapsed; equal to express some principle, would be velocities being added in equal times. of no value. An uniform force, therefore, was defined, a force which adds equal velocities in equal times. So, again, "The establishment, therefore, of a right definition of a term, may in defining momentum. It was al- name which denotes a class may best ready a received doctrine, that when be defined, we must know all the protwo objects impinge upon one an-perties common to the class, and all other, the momentum lost by the one the relations of causation or depenis equal to that gained by the other. dence among those properties. This proposition it was deemed necessary to preserve, not from the motive (which operates in many other cases) that it was firmly fixed in a popular belief, for the proposition in question had never been heard of by any but the scientifically instructed; but it was felt to contain a truth: even a superficial observation of the phenomena left no doubt that in the propagation of motion from one body to another there was something of which the one body gained precisely what the other lost; and the word momentum had been invented to express this unknown something. The settlement, therefore, of the definition of momentum involved the determination of the question, What is that of which a body, when it sets another body in motion, loses exactly as much as it communicates? And when experiment had shown that this something was the product of the velocity of the body by its mass, or quantity of matter, this became the definition of momentum. The following remarks,* therefore, are perfectly just: "The business of definition is part of the business of discovery. To define, so that our definition shall have any scientific value, requires no small portion of that sagacity by which truth is detected. When it has been clearly seen what ought to be our definition, it must be pretty well known what truth we have to state. The definition, as well as the discovery, supposes a decided step in our knowledge to have been made. The writers on Logic in the Middle Ages made Definition the last stage in the progress of knowledge; and in this arrangement at least, the history of science, and the philosophy derived from the history, confirm their speculative views." For in order to judge finally how the *Nov. Org. Renov., p. 39-40. If the properties which are fittest to be selected as marks of other common properties are also obvious and familiar, and especially if they bear a great part in producing that general air of resemblance which was the original inducement to the formation of the class, the definition will then be most felicitous. But it is often necessary to define the class by some property not familiarly known, provided that property be the best mark of those which are known. M. de Blainville, for instance, founded his definition of life on the process of decomposition and recomposition which incessantly takes place in every living body, so that the particles composing it are never for two instants the same. This is by no means one of the most obvious properties of living bodies; it might escape altogether the notice of an unscientific observer. Yet great authorities (independently of M. de Blainville, who is himself a first-rate authority) have thought that no other property so well answers the conditions required for the definition. § 5. Having laid down the principles which ought for the most part to be observed in attempting to give a precise connotation to a term in use, I must now add that it is not always practicable to adhere to those principles, and that even when practicable it is occasionally not desirable. Cases in which it is impossible to comply with all the conditions of a precise definition of a name in agreement with usage occur very frequently. There is often no one connotation capable of being given to a word, so that it shall still denote everything it is accustomed to denote; or that all the propositions into which it is accustomed to enter, and which have any foundation in truth, shall remain true. Independently of accidental ambiguities, in Among the words which have un- | resemble one another in being agreedergone so many successive transi- able; but to make this the definition tions of meaning that every trace of of beauty, and so extend the word a property common to all the things Beautiful to all agreeable things, would they are applied to, or at least com- be to drop altogether a portion of mon and also peculiar to those things, meaning which the word really, though has been lost, Stewart considers the indistinctly, conveys, and to do what word Beautiful to be one. And (with- depends on us towards causing those out attempting to decide a question qualities of the objects which the word which in no respect belongs to Logic) previously, though vaguely, pointed I cannot but feel, with him, con- at, to be overlooked and forgotten. siderable doubt whether the word It is better, in such a case, to give a Beautiful connotes the same property fixed connotation to the term by rewhen we speak of a beautiful colour, stricting, than by extending its use; a beautiful face, a beautiful scene, a rather excluding from the epithet beautiful character, and a beautiful Beautiful some things to which it is poem. The word was doubtless ex- commonly considered applicable, than tended from one of these objects to leaving out of its connotation any of another on account of a resemblance the qualities by which, though ocbetween them, or more probably be- casionally lost sight of, the general tween the motions they excited; and, mind may have been habitually guided by this progressive extension it has in the commonest and most interestat last reached things very remote ing applications of the term. For from those objects of sight to which there is no question that when people there is no doubt that it was first call anything beautiful, they think appropriated; and it is at least they are asserting more than that it is questionable whether there is now merely agreeable. They think they any property common to all the things are ascribing a peculiar sort of agreewhich, consistently with usage, may ableness, analogous to that which they be called beautiful, except the pro- find in some other of the things to perty of agreeableness, which the term which they are accustomed to apply certainly does connote, but which can- the same name. If, therefore, there not be all that people usually intend be any particular sort of agreeableto express by it, since there are many ness which is common, though not to agreeable things which are never all, yet to the principal things which called beautiful. If such be the case, are called beautiful, it is better to it is impossible to give to the word limit the denotation of the term to Beautiful any fixed connotation, such those things, than to leave that kind that it shall denote all the objects of quality without a term to connote which in common use it now denotes, it, and thereby divert attention from but no others. A fixed connotation, its peculiarities. however, it ought to have; for, so long as it has not, it is unfit to be used as a scientific term, and is a perpetual source of false analogies and erroneous generalisations. This, then, constitutes a case in exemplification of our remark, that even when there is a property common to all the things denoted by a name, to erect that property into the definition and exclusive connotation of the name is not always desirable. The various things called beautiful unquestionably § 6. The last remark exemplifies a rule of terminology, which is of great importance, and which has hardly yet been recognised as a rule, but by a few thinkers of the present century. In attempting to rectify the use of a vague term by giving it a fixed connotation, we must take care not to discard (unless advisedly, and on the ground of a deeper knowledge of the subject) any portion of the connotation which the word, in however indistinct a manner, pre-cording to a certain form. We may viously carried with it. For other discuss and settle the most important wise language loses one of its inherent interests of towns or nations by the and most valuable properties, that of application of general theorems or being the conservator of ancient ex- practical maxims previously laid down, perience; the keeper-alive of those without having had consciously sugthoughts and observations of former gested to us once in the whole proages which may be alien to the ten- cess the houses and green fields, the dencies of the passing time. This thronged market-places and domestic function of language is so often over- hearths, of which not only those looked or undervalued, that a few towns and nations consist, but which observations on it appear to be ex- the words town and nation confessedly tremely required. Even when the connotation of a term has been accurately fixed, and still more if it has been left in the state of a vague unanalysed feeling of resemblance, there is a constant tendency in the word, through familiar use, to part with a portion of its connotation. It is a well-known law of the mind, that a word originally associated with a very complex cluster of ideas is far from calling up all those ideas in the mind every time the word is used: it calls up only one or two, from which the mind runs on by fresh associations to another set of ideas, without waiting for the suggestion of the remainder of the complex cluster. If this were not the case, processes of thought could not take place with anything like the rapidity which we know they possess. Very often, indeed, when we are employing a word in our mental operations, we are so far from waiting until the complex idea which corresponds to the meaning of the word is consciously brought before us in all its parts, that we run on to new trains of ideas by the other associations which the mere word excites, without having realised in our imagination any part whatever of the meaning: thus using the word, and even using it well and accurately, and carrying on important processes of reasoning by means of it, in au almost mechanical manner; so much so, that some metaphysicians, generalising from an extreme case, have fancied that all reasoning is but the mechanical use of a set of terms ac mean. Since, then, general names come in this manner to be used (and even to do a portion of their work well) without suggesting to the mind the whole of their meaning, and often with the suggestion of a very small, or no part at all of that meaning; we cannot wonder that words so used come in time to be no longer capable of suggesting any other of the ideas appropriated to them than those with which the association is most immediate and strongest, or most kept up by the incidents of life, the remainder being lost altogether, unless the mind, by often consciously dwelling on them, keeps up the association. Words naturally retain much more of their meaning to persons of active imagination, who habitually represent to themselves things in the concrete, with the detail which belongs to them in the actual world. To minds of a different description, the only antidote to this corruption of language is predication. The habit of predicating of the name all the various properties which it originally connoted, keeps up the association between the name and those properties. But in order that it may do so, it is necessary that the predicates should themselves retain their association with the properties which they severally connote. For the propositions cannot keep the meaning of the words alive, if the meaning of the propositions themselves should die. And nothing is more common than for propositions to be mechanically repeated, mechanically retained in the sions attaching odium to selfishness | meaning of a word, but it is bad to or commendation to self-sacrifice, or let any part of the meaning drop. which implied generosity or kindness Whoever seeks to introduce a more to be anything but doing a benefit in correct use of a term with which order to receive a greater personal important associations are connected, advantage in turn. Need we say that should be required to possess an acthis abrogation of the old formulas curate acquaintance with the history for the sake of preserving clear ideas of the particular word, and of the and consistency of thought would opinions which in different stages of have been a great evil? while the its progress it served to express. To very inconsistency incurred by the be qualified to define the name, we co-existence of the formulas with must know all that has ever been philosophical opinions, which seemed known of the properties of the class to condemn them as absurdities, oper- of objects which are, or originally ated as a stimulus to the re-examina- were, denoted by it. For if we give tion of the subject; and thus the very it a meaning according to which any doctrines originating in the oblivion proposition will be false which has into which a part of the truth had ever been generally held to be true, fallen were rendered indirectly, but it is incumbent on us to be sure that powerfully, instrumental to its re- we know and have considered all vival. which those who believed the proposition understood by it. The doctrine of the Coleridge school, that the language of any people among whom culture is of old date is a sacred deposit, the property of all ages, and which no one age should consider itself empowered to alter, borders indeed, as thus expressed, on an extravagance; but it is grounded on a truth, frequently overlooked by that class of logicians who think more of having a clear than of having a comprehensive meaning, and who perceive that every age is adding to the truths which it has received from its predecessors, but fail to see that a counter-process of losing truths already possessed is also constantly going on, and requiring the most sedulous attention to counteract it. Language is the depository of the accumulated body of experience to which all former ages have contributed their part, and which is the inheritance of all yet to come. We have no right to prevent ourselves from transmitting to posterity a larger portion of this inheritance than we may ourselves have profited by. However much we may be able to improve on the conclusions of our forefathers, we ought to be careful not inadvertently to let any of their premises slip through our fingers. It may be good to alter the CHAPTER V. ON THE NATURAL HISTORY OF THE § 1. IT is not only in the mode which has now been pointed out, namely, by gradual inattention to a portion of the ideas conveyed, that words in common use are liable to shift their connotation. The truth is, that the connotation of such words is perpetually varying, as might be expected from the manner in which words in common use acquire their connotation. A technical term, invented for purposes of art or science, has, from the first, the connotation given to it by its inventor; but a name which is in every one's mouth before any one thinks of defining it, derives its connotation only from the circumstances which are habitually brought to mind when it is pronounced. Among these circumstances the properties common to the things denoted by the name have naturally a principal place, and would have the sole place if language were regu |