Darwin, Charles.

3 pages (201 x 125 mm), signed "Ch. Darwin" on personal stationary watermarked Joynson Superfine; creases where previously folded, split through majority of central crease, smaller splits at other folds, final blank page with some soiling.

Darwin Correspondence Project, “Letter no. 11416,” "Letter no. 11404," and "Letter no. 11428"accessed on 26 October 2016, http://www.darwinproject.ac.uk/DCP-LETT-11404/DCP-LETT-11428

Darwin at his most kind and generous, in a detailed and thoughtful response to a curious young reader, a James Grant, who, on March 6, 1878, asked:

"...I would... be much obliged to you if you would, in two or three words, simply tell me if your doctrine of the descent of man destroys the evidence of the existence of a God looked at through nature’s phenomena."

Darwin's response in full: "March 11, 1878. Private.
Dear Sir, I should have been very glad to have aided you in any degree if it had been in my power. But to answer your question would require an essay, and for this I have not strength, being much out of health. Nor, indeed, could I have answered it distinctly and satisfactorily with any amount of strength. 
The strongest argument for the existence of God, as it seems to me, is the instinct or intuition which we all (as I suppose) feel that there must have been an intelligent beginner of the Universe; but then comes the doubt and difficulty whether such intuitions are trustworthy.
I have touched on one point of difficulty in the two last pages of my “Variation of Animals and Plants under Domestication,” but I am forced to leave the problem insoluble.
No man who does his duty has anything to fear, and may hope for whatever he earnestly desires. (...)
Ch. Darwin. 
your letter dated March 6 was received this morning."

The correspondence continued with another letter from Grant, thanking Darwin. In part: "I am much obliged to you for your having written me, for the kindly spirit in which you have done so, and for your mind upon the question the solution of which interested me. I do not feel that I can place any reliance upon instinct or intuition in relation to the existence of God... If your doctrine is wrong and dangerous, may I say that I wish you cleared of it and all error, and that I also wish your best welfare— that other-than frail life which God in Revelation offers."

Letters that deal so directly with the theological implications of Darwin's theory of natural selection are exceptionally rare.