SCIENCM. 



309 



SCIENCE: 



A Weekly Record of Scientific 

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SATURDAY, DECEMBER 25, 1880. 



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Professor Tait, in a recent number of Nature 

 (Nov. 25, 1880), directs attention to the necessity of 

 perfect definiteness of language in all scientific work. 

 *' Want of definiteness," he says, " may arise from 

 habitual laziness, but oftener indicates a desire to 

 appear to know, where knowledge is not." 



It is also claimed that scientific writers, even of the 

 present day, have not that clear comprehension, 

 which is essential, of what is subjective and that 

 which is objective, and thus much confusion arises. 

 To use Professor Tait's own language, our only 

 source of information in physical science is the evi- 

 dence of our senses. To interpret truly this evidence, 

 which is always imperfect and often wholly mislead- 

 ing, is one of the tasks set before reason. It is only 

 by the aid of reason that we can distinguish between 

 what is physically objective and what is merely sub- 

 jective. Outside us there is no such thing as noise 

 or brightness ; these no more exist in the aerial and 

 etherecl motions, which are their objective cause, 

 than does pain in the projectile which experience has 

 taught us to avoid. To arrive at the objective point 

 of Professor Tait's article, we may state that it in- 

 s a disagreement between himself and Mr. Her- 



rt Spencer, as to the real meaning of certain words, 

 the propriety of making use of them on occa- 

 sions which are mentioned. 



In one of his works, Mr. Spencer states that, 

 ' Evolution is a change from an indefinite, incoherent 

 homogeneity, to a definite heterogeneity, through con- 

 tii uous differentiations and integrations." 



Mr. Kirkman translates the foregoing into "plain En- 

 lish," or as Professor Tait rather profanely asserts, 

 "strips it of the tinsel of high flown and unintelligible 

 language," thus : 



" Evolution is a change from a nohowish, untalka- 

 boutable, all-alikeness, to a somehowish and in- 

 general talkaboutable not-all-alikeness, by continuous 

 somethingelsifications and sticktogetherations." 



Mr. Spencer claims that the explanation of the 

 meaning of the word " Evolution " is a formula. 

 Professor Tait calls this " a definition ;" hence the 

 difference of opinion, the latter asserting it to be not a 

 mere quibble of words, but that an important scien- 

 tific distinction is involved, to which the attention of 

 the scientific world is directed. 



The perusal of a communication from Professor 

 Asaph Hall, of Washington, which will be found in 

 this column, will greatly assist those who desire to 

 solve the question. Professor Hall does not enter 

 into any details of the controversy, but offers " an 

 illustration " which appears to strike at the root of the 

 matter in dispute. 



We think that Mr. Spencer may rest satisfied with 

 applying the term " definition " to his form of words, 

 for by the rule presented by Professor Hall, it is evi- 

 dently straining a point to assert that in them we find " a 

 formula" using that word in the same sense as when 

 we speak of the law of gravitation. 



By the law of gravitation astronomers are able to 

 predict the positions of known celestial bodies four 

 years before the event, and Professor Tait asks if Mr. 

 Spencer, with his " formula," can predict, four years 

 before hand, the political and social changes which 

 will happen in the history of Europe. 



AN ILLUSTRATION. 



In regard to the controversy between Professor 

 Tait and Mr. Herbert Spencer, I beg to offer the fol- 

 lowing illustration. If we take by chance the three 

 numbers n, 12, 13, and form their squares, we have 



(n) 2 = 121 



(I2)' 2 = 144 

 (I3) 5 = 169 



Now take the numbers with the figures in an in- 

 verted order, and we have, 



(n) 2 = 121 



(21) 2 = 441 

 (31) 2 = 961 



We see that the figures of the squares are also invert- 

 ed j and this holds in the case of three consecutive 

 numbers. We infer therefore that this is a general 

 law in the formation of square numbers. Arguments 

 of this kind might have an extended application in 

 various branches of science ; but if we make further 

 examination we soon find numerous exceptions to our 



