194 PART IV PREPARATORY STAGE. 



CONCLUSION 8. 



Need of taking advantage of Special Scientific Methods, of 



utilising Existing Knowledge, of having regard to the Future, 



and of allowing for Personal Equation and for Training. 



83. (A) RECOGNISED SCIENTIFIC METHODS.-The 

 following methods are among those generally applied: (a) Ap- 

 proaching the remote and unknown from the side of the 

 known and near, including analogy, as in geology and history ; 



(b) proceeding by the law of probability, of approximation, or 

 of averages, as in the social and anthropological sciences; 



(c) applying the comparative method, as in zoology, therapeutics, 

 and psychology, and quite generally the geographical method, 

 that is, allowing for possible factual differences to be found 

 in different localities ; (d) employing separately or together the 

 historical, the genetic, and the evolutionary methods, as in bio- 

 logical, economic, aBsthetic, and many other kinds of investiga- 

 tions; (e) using the teleological method, as in ethics, or in 

 botany e.g., the adaptation of flowers to pollen-carrying 

 insects; (/) approaching the complex and abstract from the side 

 of the simple and concrete, as illustrated by diagrammatic pro- 

 cedure and in Conclusion 19 ; and (g) imagining ideally simpli- 

 fied instances, as in astronomy or mechanics. According to 

 circumstances, as many of these methods as possible should be 

 employed in an enquiry. Of capital importance are (c) and (d). 

 In connection with (d) it should be remembered that, if suffi- 

 ciently brief or extensive periods are allowed for, time almost 

 always makes a crucial difference, and in this respect it is 

 advisable to extend the criterion to the future as well as to 

 the past and present to infinity backwards and forwards, 1 so 

 far as the largest problems are concerned. All these methods 

 are treated by implication in the subsequent Conclusions, and 

 are, as above intimated, individually more applicable to one 

 department of knowledge than to another. 



A treacherous method is undoubtedly that of analogy. 2 Let 

 us provide a modern instance of this. Darwin repeatedly com- 

 pared the "intelligence" of animals with the intelligence of 

 human beings, and from his day to ours these comparisons 



1 "The student who takes an equal interest in the history of the past, 

 the development of the present, and the destinies of the future, keeps his 

 mind balanced." (Mary E. Boole, Logic Taught by Love, p. 160.) 



2 "An argument from analogy is an inference that what is true in a 

 certain case is true in a case known to be somewhat similar, but not known 

 to be exactly parallel, that is, to be similar in all the material circumstances." 

 (Mill, Logic, bk. 5, ch. 5, 6.) We should sharply distinguish analogies from 

 homologies. The latter are of considerable moment in science, e.g., inter- 

 minable homologies of structure have been discovered in the domain of 

 biology, and the sciences of heat, light, and electricity, are homologous so 

 far as undulatory motion and velocity of transmission are concerned. The 

 comparative method, as in reasoning from animals to man, occupies an 

 intermediate position, and requires scrupulous checking. 



