Thoughts in a Haystack

This mystery guest won't be one for long if you Google the quoted selection, so here are some clues beforehand that might interest you in him beyond his name.

At the age of twenty-five this gentleman was accidentally blinded by his father while the two men were out hunting, when an errant aim caused two small shot to strike him, and, in a strange chance, one entered each eye. Despite this, he became a professor at Cambridge University, a member of Parliament and, eventually, Postmaster General.

As a friend of John Stuart Mill, this guest was the person who passed on Mill's seeming approval of Darwin's method as "in the most exact accordance with the strict principles of logic." This news came at perhaps Darwin's emotional low point, as negative reactions to the Origin kept coming in, including that of another great philosopher of science, John Herschel, who called Darwin's work "the law of higgeldy-piggeldy." Darwin sighed that "I began to think that perhaps I did not understand at all how to reason scientifically." As David L. Hull, in his book, Darwin and His Critics: The Reception of Darwin's Theory of Evolution by the Scientific Community, points out, the satisfaction Darwin took from Mill's reported remark might have been misplaced:

On closer examination, however, Mill's endorsement can be seen to be not nearly reassuring. Darwin had properly used the Method of Hypothesis, but this method belonged to the logic of discovery, not proof. In spite of twenty years' labor, Darwin had failed to provide proof for his theory of evolution by natural selection.

Darwin himself was infected with the distrust of hypothesis common in the philosophy of science of his day, considering "a strong tendency to generalize as an entire evil." But, ultimately, Darwin knew it couldn't be done without:

About thirty years ago there was much talk that geologists ought only to observe and not theorise; and I well remember some one saying that at this rate a man might as well go into a gravel-pit and count the pebbles and describe the colours. How odd it is that anyone should not see that all observation must be for or against some view if it is to be of any service!

But on to the guest, who, common enough for his day -- so unlike our own -- saw no conflict between science and theology:

... [T]he statement that a new species has appeared is tantamount to the assertion that a living form has been introduced upon the earth which cannot have been generated from anything previously living. It therefore becomes necessary to suppose that the same effort of Creative Will, which originally placed life upon this planet, is repeated at the introduction of every new species; and thus a new species has to be regarded as the offspring of a miraculous birth. We are as powerless to explain by physical causes this miracle as we are any other. To hope for an explanation would be as vain as for the human mind to expect to discover by philosophy the agency by which Joshua made the sun and moon stand still. ... Those, therefore, who attempt to render unnecessary the belief in these continuously-repeated creative fiats, seek to explain hitherto unexplained phenomena of the highest order of interest and importance in natural history. Whenever this explanation shall have been given, a similar service will have been done to this science, as was performed by Newton for astronomy, when he enunciated his law of gravitation. Newton's discovery is now found in numerous religious works as a favourite illustration of the wisdom of the Creator; and it is now considered that a hymn of praise is sung to God when we expound the simplicity of the Newtonian laws. The day will doubtless come when he who shall unfold, in all their full simplicity, the laws which regulate the organic world, will be held, as Newton is now, in grateful remembrance for the service he has done not only to science, but also to religion.