"For myself, also, I rejoice profoundly; for, thinking of so many cases of men pursuing an illusion for years, often and often a cold shudder has run through me, and I have asked myself whether I may not have devoted my life to a phantasy. Now I look at it as morally impossible that investigators of truth, like you and Hooker, can be wholly wrong, and therefore I rest in peace."
He now discussed the arguments:
"About the weak points I agree. The eye to this day gives me a cold shudder, but when I think of the fine known gradations, my reason tells me I ought to conquer the cold shudder." "I remember well the time when the thought of the eye made me cold all over, but I have got over this stage of the complaint, and now small trifling particulars of structure often make me feel uncomfortable. The sight of a feather in a peacock's tail, whenever I gaze at it, makes me sick!"
(The life and Letters of Charles Darwin, John Murray, London, Vol.2, p296, 1887)
Can he really mean that? Why did he feel like that?