122 



SCIENCE 



[N. S. Vol. XXXIII. No. 839 



study of the general principles of securing 

 accuracy. 



If you will examine frankly your own 

 opinions and those of your acquaintance 

 you will, it may be presumed, quickly ac- 

 knowledge that many, perhaps most, of the 

 opinions are not of scientific accuracy. 

 On the contrary, they are, to a large ex- 

 tent, mental habits and the result of the 

 summation and averaging of impressions. 

 I, for example, know a generous man, but 

 can give very little of the evidence on 

 which my opinion is based. I know a sea- 

 coast on which fog occurs in summer quite 

 frequently, yet I can not state how often 

 the fog occurs nor just when I have ob- 

 served it. At sundry times I have received 

 an impression, in one case of the man's 

 generosity, in the other of fog. The exact 

 data can not be recalled, but the impres- 

 sion on my mind has been fixed by repeti- 

 tion. The evidence is lost, but the conclu- 

 sions persist and are accepted by me as 

 correct. For my practical needs they are 

 sufficient. We get along in ordinary life 

 satisfactorily enough with opinions thus 

 formed by summation. Most human opin- 

 ions, even when they are merely imitative, 

 originate in this way, and are correspond- 

 ingly unreliable. If we seek to explain the 

 fallibility of ordinary opinions and testi- 

 mony must we not attribute it to the 

 absence of the detailed evidence and the 

 consequent impossibility of verifying the 

 testimony ? 



We are thus led to recognize the pres- 

 ervation of the evidence as the fundamen- 

 tal characteristic of scientific work, by 

 which it differs radically from the practise 

 of ordinary life. I venture accordingly to 

 define the method of science as the art of 

 making durable trustworthy records of 

 natural phenomena. The definition may 

 seem at first narrow and insufficient, but I 

 hope to convince you that it is so compre- 



hensive as to be not only adequate, but also 

 almost complete. 



All science is constructed out of the per- 

 sonal knowledge of individual men. Sci- 

 ence is merely the collated record of what 

 single individuals have discovered. Ac- 

 cordingly, we must consider, first, the way 

 in which the individual knowledges are 

 recorded and collated. The process begins, 

 of course, with the publications of the spe- 

 cial scientific memoir in which the investi- 

 gator records his original observations and 

 makes known his conclusions. Permit me 

 to quote from Oldenburg's preface to the 

 first volume of the Philosophical Transac- 

 tions of the Royal Society. The date is 

 1665. 



Whereas there is nothing more necessary for 

 promoting the improvements of Philosophical 

 Matters, than the communicating to such, as 

 apply their Studies and Endeavours that way, 

 such things as are discovered or put in practice 

 by others; it is therefore thought fit to employ 

 the Press, as the most proper way to gratifle 

 those, whose engagement in such Studies, and 

 delight in the advancement of Learning and 

 profitable Discoveries, doth entitle them to the 

 knowledge of what this Kingdom, or other parts 

 of the World, do, from time to time, afford as 

 well of the progress of the Studies, Labours and 

 attempts of the Curious and Learned in things 

 of this kind, as of their compleat Discoveries and 

 performances. 



All that he says is true to-day, although 

 our taste has changed in favor of shorter 

 sentences. 



It is interesting to note that our present 

 standards for original memoirs have devel- 

 oped gradually. In Harvey's essay on the 

 circulation of the blood, published in 1628, 

 there are no precise data as to his observa- 

 tions. The author does not think it neces- 

 sary to specify how he has laid bare the 

 heart or how often he has repeated his 

 observations. His descriptions of the beat- 

 ing heart are vividly realistic. He writes 

 with conviction and authority. The reader 



