I rather demur to one sentence of yours, viz "however delightful any scientific pursuit may be, yet if it shall be wholly unapplied it is of no more use than building castles in the air". Would not your hearers infer from this that the practical use of each scientific discovery ought to be immediate & obvious to make it worthy of admiration? What a beautiful instance Chloriform is of a discovery made from purely scientific researches, afterwards coming almost by chance into practical use. For myself I would, however, take higher ground, for I believe there exists, & I feel within me, an instinct for truth, or knowledge or discovery, of something same nature as the instinct of virtue, & that our having such an instinct is reason enough for scientific researches without any practical results ever ensuing from them.
[Charles Darwin, Letter to John Stevens Henslow, 1 April 1848.]
