"You know what thought did" is a catch-phrase addressed to someone who has just made a stupid mistake and attempted to excuse himself by saying "But I thought..."

Does anyone know the origin of this saying; in particular, does anyone know what thought actually did?


This was a common one in our house while I was growing up. The next line was "Followed a muck cart, and thought it was a wedding". I've no source, but a quick googling suggests we weren't the only ones.

  • The variant used by my mother (and apparently fairly common in Scotland and northern England) was "... planted a feather and thought it would grow into a hen". – Kevin ORourke Jan 26 '11 at 15:03
  • 1
    This doesn't even attempt to explain the origin of the saying. – Mari-Lou A Apr 23 '17 at 8:08
  • No, but it does answer the OP's question "in particular, does anyone know what thought actually did?" – Simon Apr 23 '17 at 10:45
  • In my family, I always heard the answer as "jumped on a mutton cart, and thought it was a wedding", although I may have misheard "muck" as "mutton" as a child. It's strange that our two versions are so similar. I'm interested where you are from - I grew up in Chester, but my late father (who regularly used this phrase) was originally from Ripon. Unfortunately we are still not any closer to finding out where this phrase originated. – Kidburla Jul 17 '19 at 14:39

The Dictionary of Catch Phrases states that the original form of "You know what thought did?" is:

What did thought do?

and was exemplified in Jonathan Swift's, 'Polite Conversation', 1738

LADY ANSWERALL: I thought you did just now.
LORD SPARKISH: Pray, Madam, what did thought do?

It's also seen in Lincolnshire Traditional Sayings And Proverbial Expressions.

When a child says "I thought so and so" the adult may respond with, "You know what thought did? He only thought he did." A teenager, however, may reply, "Ah, but when he looked he had!" — a riposte which has the effect of counteracting the adult's attempt to control behaviour.


Not the answer you're looking for? Browse other questions tagged or ask your own question.