I863-] MR. BENTHAM. 209 



C. Darwin to G. Bent ham. 



Down, May 22 [1863]. 



My dear Bentham, — I am much obliged for your kind 

 and interesting letter. I have no fear of anything that a man 

 like you will say annoying me in the very least degree. On 

 the other hand, any approval from one whose judgment and 

 knowledge I have for many years so sincerely respected, will 

 gratify me much. The objection which you well put, of cer- 

 tain forms remaining unaltered through long time and space, 

 is no doubt formidable in appearance, and to a certain ex- 

 tent in reality according to my judgment. But does not the 

 difficulty rest much on our silently assuming that we know 

 more than we do ? I have literally found nothing so difficult 

 as to try and always remember our ignorance. I am never 

 weary, when walking in any new adjoining district or country, 

 of reflecting how absolutely ignorant we are why certain old 

 plants are not there present, and other new ones are, and 

 others in different proportions. If we once fully feel this, 

 then in judging the theory of Natural Selection, which im- 

 plies that a form will remain unaltered unless some alteration 

 be to its benefit, is it so very wonderful that some forms should 

 change much slower and much less, and some few should have 

 changed not at all under conditions which to us (who really 

 know nothing what are the important conditions) seem very 

 different. Certainly a priori we might have anticipated that 

 all the plants anciently introduced into Australia would have 

 undergone some modification ; but the fact that they have 

 not been modified does not seem to me a difficulty of weight 

 enough to shake a belief grounded on other arguments. I 

 have expressed myself miserably, but I am far from well 

 to-day. 



I am very glad that you are going to allude to Pasteur ; I 

 was struck with infinite admiration at his work. With cordial 

 thanks, believe me, dear Bentham, 



Yours very sincerely, 



Ch. Darwin. 



