THE AIM. AND ACHIEVEMENTS OF SCIENTIFIC METHOD. 129 



duplicate skeleton, a sufficiently authenticated photograph of 

 Diplodocus in the flesh, a souvenir of a Martian visit to Earth 

 in Jurassic times ! At any rate, there can be no doubt that 

 the man who feels that the evolutionary hypothesis gives a 

 satisfactory explanation of existing biological facts, believes in 

 the vast majority of cases that it does so because it supplies 

 the " missing links " of a spatio-temporal chain, all of which 

 could have been verified by a human observer if he had been 

 present. 



61. 



An important sub-class of this type is formed by hypotheses 

 of an " ejective " character. The counsel in the court of law 

 who seeks to persuade the jury that the accused was actuated 

 by certain motives, .or had a certain intention, is employing an 

 hypothesis of such a kind. It is clear that it has the marks 

 of conformity with our experience and (in a certain sense) of 

 homogeneity with the facts between which it is interpolated. 

 On the other hand, it is essentially un verifiable. Whether such 

 hypotheses as " attraction " or .the concept of " vital force " 

 should be included here is doubtful, They can hardly be so 

 included unless they can be said in the given cases to be 

 interpolations conformable with our experience. Thus we are 

 undoubtedly conscious of attraction and repulsion, but are we, 

 therefore, entitled to " eject " them into the matter of a planet ? 

 Much depends here upon the general character of our convic- 

 tions. Thus Gilbert of Colchester could write in 1600, 

 * Miserable were the condition of the stars, abject the lot of 

 the earth, if that wonderful dignity of life be denied them, 

 which is conceded to worms, ants, moths, plants, and toad- 

 stools."* From such a standpoint there can be little doubt that 

 "attraction" falls fairly into the present class of hypotheses. 

 For the modern physicist who belongs to a generation that has 

 learnt to disbelieve in consciousness where there is no evidence 



* De Magnete (Eng. ed., publ. by the Gilbert Club, 1900, p. 209). 



K 



