398 POPULAR SCIENCE MONTHLY. 



having been displaced in its course by the action of some quite un- 

 known laws. Would you have him say that its fall at some particular 

 place and time was 'ordained and guided without doubt by an in- 

 telligent cause on a preconceived and definite plan?' Would you not 

 call this theological pedantry or display? I believe it is not pedantry 

 in the case of species., simply because their formation has hitherto 

 been viewed as beyond law; in fact, this branch of science is still with 

 most people under its theological phase of development. The con- 

 clusion which I always come to after thinking of such questions is 

 that they are beyond the human intellect; and the less one thinks on 

 them the better. You may say, Then why trouble me? But I should 

 very much like to know clearly what you think. 



To Asa Gray. 



Down, Nov. 29th [1859]. 



This shall be such an extraordinary note as you have never received 

 from me, for it shall not contain one single question or request. I 

 thank you for your impression on my views. Every criticism from 

 a good man is of value to me. What you hint at generally is very, 

 very true: that my work will be grievously hypothetical, and large 

 parts by no means worthy of being called induction, my commonest 

 error being probably induction from too few facts. I had not thought 

 of your objection of my using the term 'natural selection' as an 

 agent. I use it much as a geologist does the word denudation for an 

 agent, expressing the result of several combined actions. I will take 

 care to explain, not merely by inference, what I mean by the term; 

 for I must use it, otherwise I should incessantly have to expand it into 

 some such (here miserably expressed) formula as the following: 

 "The tendency to the preservation (owing to the severe struggle for 

 life to which all organic beings at some time or generation are ex- 

 posed) of any, the slightest, variation in any part, which is of the 

 slightest use or favourable to the life of the individual which has thus 

 varied; together with the tendency to its inheritance." Any varia- 

 tion, which was of no use whatever to the individual, would not be 

 preserved by this process of 'natural selection.' But I will not weary 

 you by going on, as I do not suppose I could make my meaning clearer 

 without large expansion. I will only add one other sentence: several 

 varieties of sheep have been turned out together on the Cumberland 

 mountains, and one particular breed is found to succeed so much bet- 

 ter than all the others that it fairly starves the others to death. I 

 should here say that natural selection picks out this breed, and would 

 tend to improve it, or aboriginally to have formed it. . . . 



