“Ridicule may be the evidence of wit or bitterness and may gratify a little mind, or an ungenerous temper, but it is no test of reason or truth.”

"Alas, All Human" in Magazine of Fantasy and Science Fiction, June 1979
General sources

Part 3, Section 16
A Treatise of Human Nature (1739-40), Book 1: Of the understanding

6 February 1752
Letters to His Son on the Art of Becoming a Man of the World and a Gentleman (1774)

"On Truth" in Damn! A Book of Calumny (1918), p. 53
1910s
Context: The final test of truth is ridicule. Very few dogmas have ever faced it and survived. Huxley laughed the devils out of the Gadarene swine. Not the laws of the United States but the mother-in-law joke brought the Mormons to surrender. Not the horror of it but the absurdity of it killed the doctrine of infant damnation. But the razor edge of ridicule is turned by the tough hide of truth. How loudly the barber-surgeons laughed at Huxley—and how vainly! What clown ever brought down the house like Galileo? Or Columbus? Or Darwin?... They are laughing at Nietzsche yet...

Source: Julian Comstock: A Story of 22nd-Century America (2009), p. 389

Vol. 1, p. 11; "A Letter Concerning Enthusiasm".
Characteristicks of Men, Manners, Opinions, Times (1711)

Source: The Roving Mind (1983), p. 43
Context: Don't you believe in flying saucers, they ask me? Don't you believe in telepathy? — in ancient astronauts? — in the Bermuda triangle? — in life after death?
No, I reply. No, no, no, no, and again no.
One person recently, goaded into desperation by the litany of unrelieved negation, burst out "Don't you believe in anything?"
"Yes", I said. "I believe in evidence. I believe in observation, measurement, and reasoning, confirmed by independent observers. I'll believe anything, no matter how wild and ridiculous, if there is evidence for it. The wilder and more ridiculous something is, however, the firmer and more solid the evidence will have to be."

Letters On a Regicide Peace (1796)

No. 225.
The Tatler (1711–1714)
Context: At the same time that I think discretion the most useful talent a man can be master of, I look upon cunning to be the accomplishment of little, mean, ungenerous minds. Discretion points out the noblest ends to us, and pursues the most proper and laudable methods of attaining them: cunning has only private selfish aims, and sticks at nothing which may make them succeed. Discretion has large and extended views, and, like a well-formed eye, commands a whole horizon: cunning is a kind of short-sightedness, that discovers the minutest objects which are near at hand, but is not able to discern things at a distance. Discretion the more it is discovered, gives a greater authority to the person who possesses it: cunning, when it is once detected, loses its force, and makes a man incapable of bringing about even those events which he might have done had he passed only for a plain man. Discretion is the perfection of reason, and a guide to us in all the duties of life: cunning is a kind of instinct, that only looks out after our immediate interest and welfare. Discretion is only found in men of strong sense and good understandings, cunning is often to be met with in brutes themselves, and in persons who are but the fewest removes from them.