168 THE THEORY OF EVOLUTION 



living things is in a position to estimate the strength 

 and the weakness of such testimony as has passed 

 before us. That does not for a moment imply that 

 we are here dealing with esoteric mysteries which the 

 laity are unable to comprehend and must accept on 

 faith. The detective's work must convince the 

 jury and in this case, the jury is the body of intelli- 

 gent, non-professional opinion. I merely wish to 

 point out that such an exposition as I have been 

 able to make, in elementary and non-technical 

 fashion, is less convincing than the whole body of 

 known facts is to those who are familiar with it. 



From the very nature of the case, complete de- 

 monstration is impossible; we can only determine 

 which one of alternative explanations is most in 

 harmony with observation and best explains all the 

 facts, which one is therefore the most probable. 

 What gives great weight to the evidence in support 

 of the evolutionary theory is the harmonious con- 

 currence of so many independent lines of testimony. 

 Whether we deal with classification, or the results 

 of domestication, with comparative anatomy, em- 

 bryology, blood tests, palaeontology, geographical 

 distribution, or experimental investigation, we find 

 in every instance that the simplest, most satisfactory 

 and least forced interpretation is that which is 

 offered by the theory of evolution. The probability 

 rises in geometrical ratio with each additional, in- 

 dependent class of evidence. 



The pathway of science is strewn with the wrecks 



