226 CONTINUITY. 



one hand a theory is not to be accepted because it is new and 

 primd facie plausible, still to this assembly I need not say 

 that its running counter to existing opinions is not necessarily 

 a reason for its rejection ; the onus probandi should rest on 

 those who advance a new view, but the degree of proof must 

 differ with the nature of the subject. The fair question is, 

 Does the newly-proposed view remove more difficulties, re- 

 quire fewer assumptions, and present more consistency with 

 observed facts than that which it seeks to supersede ? If so, 

 the philosopher will adopt it, and the world will follow the 

 philosopher after many days. 



It must be borne in mind that, even if we are satisfied 

 from a persevering and impartial enquiry that organic forms 

 have varied indefinitely in time, the causa causans of these 

 changes is not explained by our researches ; if it be admitted 

 that we find no evidence of amorphous matter suddenly 

 changed into complex structure, still why matter should be 

 endowed with the plasticity by which it slowly acquires 

 modified structure is unexplained. If we assume that con- 

 tinuous effort, natural selection, or the struggle for existence, 

 coupled with the tendency of like to reproduce like, gives 

 rise to various organic changes, still our researches are at 

 present uninstructive as to why like should produce like, why 

 acquired characteristics in the parent should be reproduced in 

 the offspring. Reproduction itself is still an enigma, and this 

 great question may involve deeper thoughts than it would be 

 suitable to enter upon now. 



Perhaps primd facie the most striking argument in favour 

 of continuity which could be presented to a doubting mind 

 would be the difficulty it would feel in representing to itself 

 any per saltum act of nature. Who would not be astonished 

 at beholding an oak tree spring up in a day, and not from 

 seed or shoot ? We are forced by experience, though often 

 unconsciously, to believe in continuity as to all effects now 

 taking place ; if any one of them be anomalous we endeavour, 

 by tracing its history and concomitant circumstances, to find 

 its cause, i.e. to relate it to antecedent phenomena ; are we 

 then to reject similar enquiries as to the past ? Is it laudable 

 to seek an explanation of present changes by observation, 



