NA TURE 



609 



THURSDAY, OCTOBER 25, 1888. 



EMPIRICISM VERSUS SCIENCE. 



THERE is among the general public a perennial 

 tendency to exalt and honour the man of affairs — 

 the man whose business it is to pose as figurehead and 

 carry through great schemes in the face of the community — 

 at the expense of the quiet student or the scientific pioneer. 

 And every now and then this permanent tendency is 

 played upon by someone who ought to know better, and 

 excited into more conspicuous vitality ; sometimes taking 

 the form of a demonstration in favour of " practice " as 

 opposed to " theory," sometimes the form of a flow of 

 ribaldry against scientific methods and results. Such a 

 periodical outburst seems to have broken loose just now, 

 and the technical press is full of scoffs at men of science, 

 and glorification of the principle of rule-of-thumb. 



It is easy for students of science to smile at the ab- 

 surdities thus propounded and to take no further notice. 

 It is only statements which have a germ of truth about 

 them that are able really to bite and sting. And if a feel- 

 ing of momentary irritation is excited by reading some 

 piece of extra absurdity set forth for the unedification and 

 misleading of the public, the best antidote is a return to 

 one's own work, and silence. 



It is possible, however, sometimes to carry complais- 

 ance too far. " If you make yourself a sheep," was one of 

 Franklin's mottoes, " the wolves will eat you " ; and there 

 is sound worldly wisdom in the maxim, though it may be 

 difficult always to reconcile it with some other precepts 

 of a higher authority. 



The only really irritating thing about these attacks is 

 that they do not call things by their right names : if they 

 did, the absurdity would be too glaring for anyone of 

 importance to be taken in. So they sing the praises of 

 empiricism and decry science under the totally false and 

 misleading names of" practice" and "theory" respectively. 

 Now plainly there is no real antithesis possible between 

 theory and practice unless one is right and the other 

 wrong or incomplete. If both are right, they must agree. 

 If one is conspicuously right and the other conspicuously 

 wrong, it is a very cheap and simple matter to distribute 

 praise and blame. 



Whenever there is discordance between theory and 

 practice — a theory which says how a thing ought to be 

 done, and the practice by which its doing has hitherto 

 been attempted— manifestly there is something wrong 

 with one or other of them. The blame should be applied 

 to the error, and the error may lie equally well on either 

 side. The practice in early steam-engines was to cool the 

 cylinder at every stroke in order to condense the steam. 

 It certainly did condense the steam, and was therefore 

 successful. The self-styled " practical man " of that day 

 would most likely have derided any small-scale laboratory 

 experiments as futile and ridiculous, and not correspond- 

 ing to the conditions of actual work. Nevertheless, that 

 eminent theorist, James Watt, by studying the behaviour 

 of saturated steam under various circumstances in a 

 scientific manner, and by discovering that the pressure in 

 any connected system of vessels containing vapour would 

 rapidly become equal to the vapour-tension corresponding 

 Vol. *»*xviii.— No. 99 1 * 



to the coldest, did succeed in introducing a noteworthy 

 improvement into a time-honoured practice. Again, the 

 question of the specific heat of saturated steam, whether 

 it be zero, or positive, or negative, is a highly scientific 

 question, first solved on the side of theory by Clausius.an 

 eminent example of the purely scientific worker ; but the 

 fact that it is negative has an immediate practical bearing 

 on the important subject of steam-jacketing, and fully 

 explains the advantage of that process. 



But it may be said the advantage of the steam-j acket 

 was discovered by experience. Very likely. It is a con- 

 spicuous and satisfactory fact that progress can be made 

 in two distinct ways. Sometimes the improvement is 

 discovered by what may be termed blindfold experience : 

 a certain operation turns out to be uniformly successful, 

 and, without any further knowledge, that is sufficient 

 justification of its performance. The observed fact that 

 inhalations of chloroform produced temporary anaesthesia 

 was sufficient justification of its use in surgery without 

 any theory as to why it so acted. The motion of the 

 planets in ellipses, according to certain laws, might have 

 been deduced from the theory of gravitation ; but 

 historically those motions were deduced by a laborious 

 comparison of observations. Sometimes observation is 

 ahead of theory ; sometimes theory is ahead of observation. 

 It is mere nonsense to decry either on that account. 



It is also absurd to deny that our knowledge of a fact, 

 and our confidence in its use, and of all the conditions 

 under which it may be used or may not be used, are enor- 

 mously enhanced when one knows not only the bare fact by 

 observation empirically, but when also one thoroughly 

 understands the reasons and the laws connected with it. 

 It would be justifiable to employ a successful drug even 

 if one knew nothing of its mode of action, and could give 

 no reason for its effects ; but it is far more satisfactory 

 to understand it exactly, and to have a complete theory 

 of its physiological action. One can then decide before- 

 hand, without empiricism, or a possibly fatal experiment, 

 under what circumstances and to what constitutions it 

 would be noxious. 



The fact that lightning-conductors are often successful 

 is ample justification for their use, but it will be far more 

 satisfactory when, by help of laboratory experiments and 

 theory, one understands all the laws of great electrical 

 discharges, and can provide with security against their 

 vagaries. 



These things are truisms, but it would seem to be 

 sometimes necessary to utter truisms. 



Sometimes one hears a judgment such as this : " Yes, 

 he is a very good man in some ways, but he is too much 

 of a theorist." And then there is a sapient shaking of 

 heads, as if the term "theorist" were an intelligible term 

 of abuse. You suppose it means that the wretched man 

 knows too much about the mode of working of things ; too 

 much about the strength of materials, too much about 

 graphical statics, if he is engaged in building a bridge ; 

 but if you ask the meaning of the fatal term, you 

 find it explained in some such way as that " he does not 

 attend to details," or " he does not look after his work- 

 men," or " he accepts rotten materials." Then why not 

 apply some term which shall legitimately mean these 

 things, such as careless, or lazy, or ignorant, or un- 

 businesslike ? Probably the word " theorist " as a term 



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