ORIGIN AND AGE OF THE SUNS HEAT. 289 



the most formidable objections to the theory of 

 evolution is the enormous length of time which it 

 demands. On this point Prof. Haeckel, one of the 

 highest authorities on the subject, in his "History of 

 Creation, " has the following : — " Darwin's theory, as 

 well that of Lyell, renders the assumption of immense 

 periods absolutely necessary. ... If the theory of 

 development be true at all there must certainly have 

 elapsed immense periods, utterly inconceivable to us, 

 during which the gradual historical development of 

 the animal and vegetable proceeded by the slow 

 transformation of species. . . The periods during 

 which species originated by gradual transmutation 

 must not be calculated by single centuries, but by 

 hundreds and by millions of centuries. Every process 

 of development is the more intelligible the longer it is 

 assumed to last." 



There are few evolutionists, I presume, who will 

 dispute the accuracy of these statements; but the 

 question arises, does physical science permit the 

 assumption of such enormous periods ? We shall now 

 consider the way in which Prof. Haeckel endeavours 

 to answer this question and to meet the objections 

 urged against the enormous lapse of time assumed for 

 evolution. 



"I beg leave to remark," he says, "that we have not 

 a single rational ground for conceiving the time 

 requisite to be limited in any way. ... It is 

 absolutely impossible to see what can in any way limit 

 us in assuming long periods of time. . . . From a 

 strictly philosophical point of view it makes no diffe- 

 rence whether we hypothetically assume for this 

 process ten millions or ten thousand millions of years. 



. . . In the same way as the distances between 

 the different planetary systems are not calculated 1 »y 



X 



