I've long been familiar with, and laughed at, the idiom "A blind man, in a dark room, looking for a black cat that isn't there". However, I wasn't aware of its origins, or of the various ways it's been used in the past. I decided, on a whim, to look it up.
Two articles at the always useful Quote Investigator provided the answers I needed. The first article established its origins.
The earliest evidence located by QI in a Missouri newspaper in 1846 did not mention any professions; instead, the figurative language was used to illustrate the notion of darkness. Boldface has been added to excerpts:
A DARK SUBJECT—A blind negro, with an extinguished candle looking for a black cat in a dark cellar.In August 1849 a London journal called “Family Herald: A Domestic Magazine of Useful Information and Amusement” printed a short item with an acknowledgement to another magazine called “Penny Punch”. The item presented a definition of darkness ascribed to a precocious child:
A DEFINITION OF DARKNESS
Dr. Twiggem—"Indeed, for his age, sir, he’s a wonderful child. Come now, Fred., my dear, give your papa a nice lucid definition of—of—darkness."
Fred. (after a little thought, and with much sagacity)—"Please, sir, ‘a blind Ethiopian—in a dark cellar—at midnight—looking for a black cat.' "
There's more at the link.
The second article provided a humorous look at the idiom's use in philosophical and theological debate - and in less-honest legal circles.
The earliest evidence located by QI appeared ... in a 1931 book titled “Since Calvary: An Interpretation of Christian History” by the comparative religion specialist Lewis Browne. The sharpest barb was aimed at a set of religious individuals called Gnostics:
Someone has said that a philosopher looking for the ultimate truth is like a blind man on a dark night searching in a subterranean cave for a black cat that is not there. Those Gnostics, however, were theologians rather than philosophers, and so—they found the cat!. . .
In 1942 the acerbic commentator H. L. Mencken published a prodigious collection of quotations that included a concise unattributed version of the gibe:
TheologyAlso in 1942 a book reviewer in the “Cornell Law Quarterly” extended the humorous passage by contrasting three professions: philosopher, theologian, and lawyer. This citation was listed in “The Oxford Dictionary of American Legal Quotations” and “Cassell’s Humorous Quotations”:
A blind man in a dark room searching for a black cat which isn’t there — and finding it.
A philosopher is a blind man in a dark cellar at midnight looking for a black cat that isn’t there. He is distinguished from a theologian, in that the theologian finds the cat. He is also distinguished from a lawyer, who smuggles in a cat in his overcoat pocket, and emerges to produce it in triumph.
Again, more at the link.
Speaking as a once-upon-a-time theology student and now-retired pastor, I find the latter attributions very appropriate!