My dear Sir

I have had two bad days in my bed-room & am a good deal shaken & must be brief.— I sh^d. be an unfeeling wretch, if I was not quite softened by your extremely kind letter.—² I own that I thought I saw that your religious feelings had led (for I know of no other cause) you to feel personal animosity towards me, but that your kindness had induced you to conquer & mask these feelings, but that they had biassed your arguments. I now quite think that this was an utter delusion & I apologise to you for such thoughts. I express myself very badly but my head feels very weak.— I do most strongly think, & remember writing so just after appearance of Origin, that the belief in Evolution is infinitely more important for science than belief in Nat. Selection;³ but I do not wish to obtrude this opinion in any public work, or at least not without it comes in naturally & is duly guarded.— I think so, because an [immense] field of enquiry is thus opened up on the manner in which each organism has acquired its present structure—causes of variation—mutual sterility—geographical distribution &c &c &c

(By the way do not your adduced facts of anomalous distribution tell quite as much against evolution as against nat. Selection?)⁴ For my own private part, I sh^d have felt little interest in evolution if I had not been able to explain in a general manner to my own satisfaction how each organism had become so wonderfully adapted to its conditions. You admit that Nat-selection has done something, but I almost think you w^d be puzzled to say what, judging from your argument from jaw of Thylecimus.⁵ I almost think you w^d have been more secure to have followed Owen⁶ & given Nat. Selection altogether up.—

Pray tell me when I used that horrid arrogant expression—“it is a false belief”—⁷ When in London, strength & time permitting, I will surely call on you.— Accept my cordial and sincere thanks for your great kindness & for not taking offence with me.— I can write no more.— I do not know whether all this will be intelligible.

Ch. Darwin