Edukashun iz a good thing generally, but most pholks eddukate their prejudices.

[Education is a good thing generally, but most folks educate their prejudices.]

Josh Billings (1818–1885) American humorist, aphorist [pseud. of Henry Wheeler Shaw]

Everybody’s Friend, Or; Josh Billing’s Encyclopedia and Proverbial Philosophy of Wit and Humor, ch. 286 “Variety: Billings’ Proverbs” (1874)
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Sometimes misattributed to Charles Dudley Warner.

For more discussion of other quotes around this theme, see Quote Origin: People Think They Are Thinking When They Are Merely Rearranging Their Prejudices – Quote Investigator®.