“A rationalist, as I use the word, is a man who attempts to reach decisions by argument and perhaps, in certain cases, by compromise, rather than by violence. He is a man who would rather be unsuccessful in convincing another man by argument than successful in crushing him by force, by intimidation and threats, or even by persuasive propaganda.”

Letter to Evert Augustus Duyckinck (3 March 1849); published in The Letters of Herman Melville (1960) edited by Merrell R. Davis and William H. Gilman, p. 78; a portion of this is sometimes modernized in two ways:
Context: I do not oscillate in Emerson's rainbow, but prefer rather to hang myself in mine own halter than swing in any other man's swing. Yet I think Emerson is more than a brilliant fellow. Be his stuff begged, borrowed, or stolen, or of his own domestic manufacture he is an uncommon man. Swear he is a humbug — then is he no common humbug. Lay it down that had not Sir Thomas Browne lived, Emerson would not have mystified — I will answer, that had not Old Zack's father begot him, old Zack would never have been the hero of Palo Alto. The truth is that we are all sons, grandsons, or nephews or great-nephews of those who go before us. No one is his own sire. — I was very agreeably disappointed in Mr Emerson. I had heard of him as full of transcendentalisms, myths & oracular gibberish; I had only glanced at a book of his once in Putnam's store — that was all I knew of him, till I heard him lecture. — To my surprise, I found him quite intelligible, tho' to say truth, they told me that that night he was unusually plain. — Now, there is a something about every man elevated above mediocrity, which is, for the most part, instinctuly perceptible. This I see in Mr Emerson. And, frankly, for the sake of the argument, let us call him a fool; — then had I rather be a fool than a wise man. —I love all men who dive. Any fish can swim near the surface, but it takes a great whale to go down stairs five miles or more; & if he don't attain the bottom, why, all the lead in Galena can't fashion the plumet that will. I'm not talking of Mr Emerson now — but of the whole corps of thought-divers, that have been diving & coming up again with bloodshot eyes since the world began.
I could readily see in Emerson, notwithstanding his merit, a gaping flaw. It was, the insinuation, that had he lived in those days when the world was made, he might have offered some valuable suggestions. These men are all cracked right across the brow. And never will the pullers-down be able to cope with the builders-up. And this pulling down is easy enough — a keg of powder blew up Block's Monument — but the man who applied the match, could not, alone, build such a pile to save his soul from the shark-maw of the Devil. But enough of this Plato who talks thro' his nose.