168 Darwinism and Other Essays. 



demonstrated truth, and will never be susceptible 

 of the slightest change. The same is the case 

 with the truth, " It is wrong to kill." Once rec- 

 ognized, this truth can experience no change, for 

 the very reason that it is a truth, and not a false- 

 hood. In a word, when a proposition has been 

 once shown to be true it will forever remain so, 

 whether it relates to our moral obligations, or to 

 anything else whatever. There is no ground for 

 Mr. Buckle's distinction. 



Nor would our author be one whit the more 

 justified in saying, as he might say, that the inter- 

 pretation put upon " moral truths " is unchanging 

 as compared with that put upon " intellectual 

 truths." On the contrary, it appears to us that 

 the reverse is the case. When a truth relating 

 to some of the simpler subjects of investigation is 

 once received, its interpretation usually admits of 

 little change. To employ the same example as 

 before, the law of gravitation is received in the 

 same acceptation now as when it was first discov- 

 ered. Advancing to the more abstruse sciences, 

 such as physiology, we find that the interpreta- 

 tion put upon generally received truths suffers 

 marked variations. The law of organic develop- 

 ment has been held by the most eminent scientific 

 thinkers since the beginning of the present cert 



