Though Erdős used this remark, it is said to have originated with his friend Stanisław Ulam, as reported in The Man Who Loved Only Numbers : The Story of Paul Erdős and the Search for Mathematical Truth (1998) by Paul Hoffman
Variants:
The first sign of senility is when a man forgets his theorems. The second sign is when he forgets to zip up. The third sign is when he forgets to zip down.
As quoted in Wonders of Numbers : Adventures in Mathematics, Mind, and Meaning (2002) by Clifford A. Pickover, p. 64
There are three signs of senility. The first sign is that a man forgets his theorems. The second sign is that he forgets to zip up. The third sign is that he forgets to zip down.
Misattributed
Stanislaw Ulam (1909–1984) Polish-American mathematician
Attributed in Paul Hoffman, The Man Who Loved Only Numbers: The Story of Paul Erdős and the Search for Mathematical Truth (1998)
This has also been attributed, with variants, to Paul Erdős, who repeated the remark.
John Campbell Shairp (1819–1885) British writer
Source: Dictionary of Burning Words of Brilliant Writers (1895), P. 565.
Enoch Powell (1912–1998) British politician
Reacting to a youth who had given the Hitler salute; from a speech in Wolverhampton (6 June 1970), quoted in Simon Heffer, Like the Roman. The Life of Enoch Powell (Phoenix, 1999), p. 558.
1970s
“When suffering comes, we yearn for some sign from God, forgetting that we have just had one.”
Mignon McLaughlin (1913–1983) American journalist
The Complete Neurotic's Notebook (1981), Unclassified
“Doubt is not always a sign that a man is wrong; it may be a sign that he is thinking.”
Oswald Chambers (1874–1917) British missionary
“The surest sign that a man has a genuine taste of his own is that he is uncertain of it.”
W. H. Auden book The Dyer's Hand
"Reading", p. 6
The Dyer's Hand, and Other Essays (1962)
“And for a second, just for a second I forget. I forget that this isn't real.”
Jenny Han book To All the Boys I've Loved Before
Source: To All the Boys I've Loved Before
“Shut up, sit down, zip your mouth. Know that I am God.”
Glenn Beck (1964) U.S. talk radio and television host
Okay. When we have the chance, if this stuff all falls into place, that The Blaze is going through right now, I'm telling you — miracles, absolute miracles.
2014-02-12
The Glenn Beck Program
Radio, quoted in * 2014-02-12
Beck: God Told Me To Sit Down And Shut Up Because He Has 'Absolute Miracles' In Store For The Blaze
Kyle
Mantyla
RightWingWatch
http://www.rightwingwatch.org/content/beck-god-told-me-sit-down-and-shut-because-he-has-absolute-miracles-store-blaze
2014-02-05
2010s, 2014
“When a man feels that he cannot leave his work, it is a sure sign of an impending collapse.”
Louis Brandeis (1856–1941) American Supreme Court Justice
Letter to Alfred Brandeis (March 8, 1897), reprinted in Letters of Louis D. Brandeis Volume I 127 (Melvin I. Urovsky & David W. Levy, eds., State University of New York Press 1971).
Extra-judicial writings
