Philosopher, Theologian and a Lawyer

Tonight's Quote . . . . Unquote on Radio 4 began with a nice quotation I'd not heard before:

"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."

William L. Prosser, "My Philosophy of Law," Cornell Law Quarterly, 1942

I've picked up that version of it from Lawyer Jokes Etc. after having gone searching for it; on Quote . . . . Unquote I think it was given out as anon., but from 1942.