# "All x are not y" - what does this mean to you??

**URL:** <https://boards.straightdope.com/t/all-x-are-not-y-what-does-this-mean-to-you/536066>\
**Category:** In My Humble Opinion\
**Created:** [April 14, 2010, 2:43pm UTC](https://boards.straightdope.com/t/all-x-are-not-y-what-does-this-mean-to-you/536066 "2010-04-14T14:43:13Z")\
**Posts on this page:** 1\
**Page:** 3

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**Author:** ![Indistinguishable](https://avatars.discourse-cdn.com/v4/letter/i/90ced4/32.png) [@Indistinguishable](https://boards.straightdope.com/u/Indistinguishable)\
**Post date:** [April 18, 2010, 5:34am UTC](https://boards.straightdope.com/t/all-x-are-not-y-what-does-this-mean-to-you/536066/41 "2010-04-18T05:34:56Z")

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I would think the meaning “X and Y are mutually exclusive” is the academic or formal reading of “All X are not Y”, while the colloquialism is the reading of “All X are not Y” as meaning “X is not a subset of Y (i.e., not all X are Y)”.

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