“Irony deals with opposites; it has nothing to do with coincidence. If two baseball players from the same hometown, on different teams, receive the same uniform number, it is not ironic. It is a coincidence. If Barry Bonds attains lifetime statistics identical to his father's, it will not be ironic. It will be a coincidence. Irony is "a state of affairs that is the reverse of what was to be expected; a result opposite to and in mockery of the appropriate result." For instance: a diabetic, on his way to buy insulin, is killed by a runaway truck. He is the victim of an accident. If the truck was delivering sugar, he is the victim of an oddly poetic coincidence. But if the truck was delivering insulin, ah! Then he is the victim of an irony. If a Kurd, after surviving bloody battle with Saddam Hussein's army and a long, difficult escape through the mountains, is crushed and killed by a parachute drop of humanitarian aid, that, my friend, is irony writ large. Darryl Stingley, the pro football player, was paralyzed after a brutal hit by Jack Tatum. Now Darryl Stingley's son plays football, and if the son should become paralyzed while playing, it will not be ironic. It will be coincidental. If Darryl Stingley's son paralyzes someone else, that will be closer to ironic. If he paralyzes Jack Tatum's son, that will be precisely ironic.”

What is Art? (1897)
Context: The good is the everlasting, the pinnacle of our life. … life is striving towards the good, toward God. The good is the most basic idea … an idea not definable by reason … yet is the postulate from which all else follows. But the beautiful … is just that which is pleasing. The idea of beauty is not an alignment to the good, but is its opposite, because for most part, the good aids in our victory over our predilections, while beauty is the motive of our predilections. The more we succumb to beauty, the further we are displaced from the good.... the usual response is that there exists a moral and spiritual beauty … we mean simply the good. Spiritual beauty or the good, generally not only does not coincide with the typical meaning of beauty, it is its opposite.

Source: The Door Into Summer (1957), Chapter 8

“The Hill and the Hole” (p. 165); originally published in Unknown Worlds, August 1942
Short Fiction, Night's Black Agents (1947)

Source: V for Vendetta, Vol. III of X

Sleeping Murder (1976)

Rich Dad Poor Dad: What the Rich Teach Their Kids About Money-That the Poor and the Middle Class Do Not!

Brown did include this quote in her book Sudden Death (Bantam Books, New York, 1983), p. 68, but it appears she was just paraphrasing a quote that had already been written elsewhere. The earliest known appearance of a similar quote is the "approval version" of the Narcotics Anonymous "Basic Text" released in November 1981, which included the quote "Insanity is repeating the same mistakes and expecting different results." A PDF scan of the 1981 approval version can be found here http://www.nauca.us/wp-content/uploads/2015/04/1981-11-Basic-Text-Approval-Form-White.pdf, with the quote appearing on p. 11 (p. 25 of the PDF), at the end of the fourth paragraph (which begins "We have a disease; progressive, incurable and fatal"). More in this article https://quoteinvestigator.com/2017/03/23/same/ on Quote Investigator website.
Misattributed

Misattributed to various people, including Albert Einstein and Mark Twain. An early occurrence was used as a teaching reference at University of California, Irvine in social science lectures in the later 1960s. Also found in a 1981 text from Narcotics Anonymous.
Misattributed