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Comte's Positive Philosophy. By G. H. Le...
by the broadest and most natural differences . In chemical action we have evidently something more than simple physical action , and something less than vital action , notwithstanding the vague analogies that may be drawn between these three orders of phenomena on purely hypothetical considerations . The only molecular perturbations which physical activity , properly so cailedj can produce in bodies , are nothing more than modifications of the arrangement of the particles ; and those modifications which are generally of no great extent are ' most frequently of a temporary nature ; in no
case is the substance altered . Chemical activity , on the contrary , always produces an essential and permanent change in the very composition of the particles , over and above the alterations in structure and in the state of aggregation ; the bodies which were used in the phenomena are not now to be recognised , so much has the ensemble of their properties been altered . Finally , physiological phenomena manifest material activity in a degree of effected the
energy still greater ; for as soon as a chemical combination is bodies become completely inert ; whereas the vital state is characterized , not only by the physical and chemical phenomena which it constantly produces , but also by a double movement , more or less rapid , but always necessarily continuous , of composition and decomposition , capable of sustaining within certain limits of variation , and for a period more or less considerable , the organization of the body , by entirely renewing its substance without end . We thus conceive > in a way admitting of no exception , the
fundamental gradation of these three essential modes of molecular activity , which true philosophy can never permit of being confounded together . There are also two secondary considerations to be noticed respecting chemical phenomena . _ First—Every substance is , doubtless , susceptible of chemical action , and this is why chemical phenomena have been properly classed among general phenomena . They are unlike physiological phenomena , these being peculiar to certain organized substances . But still * in each case of chemical phenomena a specific difference is found . Physical properties , on the oth er hand , show only differences in degree .
Second—In order to produce chemical phenomena it is requisite that the antagonistic particles be brought into immediate contact . When the structure of the substance does not spontaneously permit this , it must be artificially attained by liquefaction , . The ensemble of the foregoing considerations may be exactly summed up by defining Chemistry as having for its general object , the study of the laws of those phenomena of composition and decomposition which result from the mutual molecular and specific action of different substances , natural or artificial . There is reason to fear , from the extreme imperfection of this science ,
that it will not permit , for a long time , of a more exact and more precise definition , capable of characterizing plainly what are in general the indispensible data , and the final unknown terms , of every chemical problem . But the idea of science is always combined with that of prevision in true philosophy , and the final aim of Chemistry ought , therefore , to be thus conceived - . —Given , the chemical properties of certain substances , simple or compound , placed in chemical relation , under well-defined circumstances , to determine exactly in what their action will consist , and what will be the principal properties of the new products . obtainedthe
Wo easily conceive that if such solutions were actually , three great and fundamental applications of chemical science—to the study of vital phenomena , to the natural history of the terrestrial globe , and , in the last place , to industrial operations—would be thereby rationally organized , instead of being , as at present , the almost accidental and irregular result of the spontaneous development of science ; seeing that in every one of these three general cases the question immediately falls within our abstract formula , the data of which are directly furnished by the particular circumstances of each application .
In examining more profoundly this rational definition of chemical science , and carrying out the principle of it another step , we shall find it susceptible of an important transformation ; for all the fundamental data of Chemistry could thus be reduced to the knowledge of the essential properties of simple substances solely , which would lead to that of the different immediate or primary combinations , and thence to the most complex and most remote . We should then have to make each simple substance the direct object of experimental study by itself . It may be that there is a certain general and necessary harmony between the chemical and physical properties of each chemicai substance ; but we cannot go the length of saying that this harmony would ever dispense with a distinct and independent chemical examination of each of these substances . But if once our knowledge of the
chemical qualities of each simple substance were completed , by observation and experiment , all the other chemical problems , notwithstanding their immense variety , would become susceptible of purely deductive solutions , by means of u small number of invariable laws , established by the true genius of Chemistry for , the different classes of combinations . Under this point of view compounds naturally present two general modes of classification , both of which necessarily require marked notice . First , The simplicity or the greater or less degree of composition of the
primary combinations . Second , The number of the combined elements , Now , observation has shown that the higher the order of composition of any substances the more difficult does chemical action botween them become ; the majority of compound atorasi belong to the two firat W & w *>
and beyond the third their combination seems almost impossible ; while under the second point of view , compounds very rapidly lose their stability ' in proportion as the number of elements is increased . Most frequently there is only a simple dualism , and scarcely any body is more than a ! quaternary . Hence the number of general chemical classes | o whi ^ ^ jg 1 tlj V . _ fold and necessary distinction can give room can never be much extended To each Of them tbere would correspond a fundamental lawof combination which , when applied to any case in hand , would deductively make known the result from the elementary data . It is to our own radical feebleness and partly to the vicious direction of our intelligence ; much more than to the peculiar nature of the subject , that we must specially attribute the cause of our being yet so very far from such a method of philosophising . However difficult it may appear at present > we ought not to forget that we find
it realized , to a certain extent , in a very important though secondar y category of chemical researches ^—the study of proportions * By the aid of a chemical co-efficient , evalued empirically for each simple substance , we are able , in numerous cases , with sufficient exactness , to determine deductively , from a small number of general laws , the proportion according to which the compounds previously known unite in each new product ; Why should not all the other branches of chemical studyallow in the end of a perfect analogy ? We may then sum up these observations b y defining Chemistry , m the most rational way possible , as haying this for its ultimate object : —Given , the properties of all simple substances , to find those of all the compounds which they can form . ; Chemistry , when compared with the preceding sciences , affords a strong verification of the law that the complexity of the sciences , and their means
of exploration , increase together . It is here that the first and the most general of the three essential niodes of investigation , which we have distinguished in Natural Philosophy , begins to receive its integral development ; until arrived $ tthis science ^ observation is in fact always more or less partial . In Astronomy , it is necessarily limited to the exclusive einplbyment of a single one of pur senses ; in Physics , hearing , and partrcularly touch , co ^ oie to the aid of sight ; but taste and smell remain essentially inactive . In Chemistry , on the contrary * all the senses simultaneously concur in the analysis of its phenomena ^ We can form a correct idea of the inCrfease of power which results & om
this convergence , by trying to picture , as far as possible , what would become of Chemistry If "it were there necessary to renounce the use of smell and taste—these very often furnishing us with the only characteristics by which we could recognise and distinguish the different effects produced . * But what the philosophical mind ought especially to observe on this subject is , that in this correspondence there is nothing accidental , nor even empirical Because the true physiological theory of sensation , clearly shows tha | the apparatus of taste and smell , unlike thpse of the otlier senses , acts in an eminently chemical way , and that , consequently , the nature of those two senses specially adapts them for perceiving the phenomena of composition and decomposition .
With regard to experiment , according to his definition of it , Comte repeats that the part it plays in Chemistry is altogether overrated , great though its efficacy undoubtedly is , and greater though it will be when thd science is cultivated more philosophically ; for chemical effects usually depend on too great a concurrence of different influences to mak ^ e it easy to throw light on the production of them by true experiments . We should have the difficult task of instituting two parallel cases , exactly identical in all their characteristic circumstances , save in that one of which . wri desire to find the value : this being the fundamental condition of all
unexceptionable experiment . The nature of philosophical investigations presents a complete obstacle to the purely experimental method , the use of which is almost always illusory there ; and it is in Chemistry , owing to the complication of its phenomena , that we first meet , with this some im * pediment , although to an infinitely less extent . Finally , with regard to the third fundamental mode of rational explore- tion , comparison , properly so called , the least general of all j it is of importance to consider here , that if this process is essentially destined for physiological studies , its employment first begins to acquire a real efficacy in chemical researches . The essential condition'of this precious method but
consists in the existence of a sufficiently extended series of analogous distinct cases , where a phenomenon common to them all is more and mo re modified , both by simplifications and by a successive and almost continuous decrease in the degree of its manifestation . Evidently , physiological phenomena can alone give complete scope for the employment of this metno . But the admitted existence of natural families in Chemistry makes it probable that , in the future progress of this infant science , a corresponding classification will yet be made , which will lead to the use of the comparative method in Chemistry , both being founded on the common consecrations of uniformity in certain preponderating phenomena displayed in along
scries of different bodies . Chemical investigations enjoy the advantage of a verification by mean of the double process of analysis and synthesis . Strictly speaking , «» e process of synthesis , though useful , may be dispensed with when tho « J « ^ of the experiment is to discover the simple elements of a given substati , whereas , when the experiment is made to find out what are thec ? mP 0 UV which immediately form the given substance , we may in appearance odp them , but in reality have got compounds produced by new combinations ^ the course of the process . In the latter case , therefore , » ynthe »» 8 w go
Sm ' " , ¦ - . . ' ' ; ' :.G;Y : B-,^:Ya...
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Citation
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Leader (1850-1860), June 12, 1852, page 20, in the Nineteenth-Century Serials Edition (2008; 2018) ncse.ac.uk/periodicals/l/issues/cld_12061852/page/20/
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