That that is is that that is not is not is that it it is

"That that is is that that is not is not is that it it is" is a grammatically correct English word sequence demonstrating syntactic ambiguity. It is used as an example illustrating the importance of proper punctuation.[1]

The sequence can be understood as any of four grammatically correct sequences, each with at least three discrete sentences, by adding punctuation:

That that is, is. That that is not, is not. Is that it? It is.

That that is is that that is. "Not" is not. Is that it? It is.

That that is is that that is not. Is "'not' is that" it? It is.

That that is is that that is not "is not". Is that it? It is.

The first, second, and fourth sentences relate a simple philosophical proverb in the style of Parmenides stating: that all that is is; and that anything that does not exist does not. The phrase was noted in Brewer's Dictionary of Phrase and Fable.[2]

This phrase appeared in the 1968 American movie Charly, written to demonstrate punctuation to the main character Charly's teacher, in a scene to demonstrate that the surgical operation to make the character smarter had succeeded.[3]

Ursula K. Le Guin uses a similar sentence in her book Steering the Craft (1998) as an exercise in punctuation: "All that is is all that is not is not that that is is not that that is not that is all." Le Guin says "All you need to make it make sense is three semicolons. You could use periods, but it would be jerky." A possible solution, not given by Le Guin, is: "All that is is; all that is not is not that; that is is not that that is not; that is all."[4]

See also

References
  1. Wieringa, Moore & Barnes (1993). Procedure Writing: Principles and Practices. Battelle Press. p. 54. ISBN 0-935470-68-9.
  2. Brewer, Ebenezer Cobham (1953). Dictionary of Phrase and Fable. Harper. p. 896.
  3. "Charly (1968)". IMDb. Retrieved 22 August 2014.
  4. Le Guin, Ursula K. (2015). Steering the Craft: A 21st Century Guide to Sailing the Sea of Story. First Mariner Books. p. 141.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.