To F. E. Abbot   30 March 1874

My dear Sir

I have rec^d your kind letter of the 3^rd & the copies of the Index.¹

You have put with remarkable clearness & correctness my views on the moral sense; & you must allow me to say that your eulogium on what I have tried to do in science is the most magnificent one ever passed on me; & I heartily wish that I deserved the half of what you say.² I have read your article with much interest & with all the attention of which I am capable. But it is the truth that from having had no practice in following abstract & abstruse reasoning, I put no trust in my own judgment in such cases. To make any point clear to myself I must put it under a concrete form. Therefore my opinion on your Essay is worth very little; & I must say that I cannot see how morality is “objective & universal”;³ yet I have approached the subject with a wish to be convinced. It w^d be of no use to give my doubts in detail; perhaps I shall best shew where my difficulty chiefly lies by the following remarks. The lower social animals may be said to be under an obligation not habitually to kill each other, & the mothers to protect their offspring. I think this mutual bond may be called an obligation, as the species c^d not exist in society without it. No one w^d call it a moral obligation, & most persons w^d call it instinctive. Would you consider this an “objective & universal fact”? I suppose certainly not, as instinct is subjective & the obligation w^d differ to a certain extent for different species. Now as soon as a social animal became in some slight, incipient degree a moral creature,—that is—was capable of approving or disapproving of its own conduct,—does it follow that its obligation w^d at once become moral? Would not the obligation remain, to a large extent, of the same so-called instinctive nature as before? And if so, its obligation could be only to a small extent objective & universal. Even if the obligation of a moral being must be of necessity moral, I cannot see why it sh^d be an objective & universal fact, any more than with the instinctive obligation or bond between the lower social animals. I have expressed myself obscurely, & I sh^d not be in the least surprized if my ideas were shewn to be quite confused; but I have thought myself bound to tell you my impression. I need not say that this letter is private, & it is obviously of no value.⁴ I much wish that I was better able to follow out abstract reasoning & that I could agree with you.

Allow me again to thank you cordially for your very kind feelings towards me; & believe me my dear Sir | yours very sincerely | Charles Darwin