# "All X is not Y" vs "Not all X is Y"

**URL:** <https://boards.straightdope.com/t/all-x-is-not-y-vs-not-all-x-is-y/716399>\
**Category:** In My Humble Opinion\
**Created:** [March 31, 2015, 5:31am UTC](https://boards.straightdope.com/t/all-x-is-not-y-vs-not-all-x-is-y/716399 "2015-03-31T05:31:18Z")\
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**Author:** ![Senegoid](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/senegoid/32/6606_2.png) [@Senegoid](https://boards.straightdope.com/u/Senegoid)\
**Post date:** [March 31, 2015, 6:14am UTC](https://boards.straightdope.com/t/all-x-is-not-y-vs-not-all-x-is-y/716399/3 "2015-03-31T06:14:33Z")

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In my Logic class, we had a chapter on formal Aristotelian Logic, with its “[Square of Opposition](http://en.wikipedia.org/wiki/Square_of_opposition)” (analysis of the forms “All X are Y”, “No X is Y”, “Some X are Y”, “Some X are not Y”).

The phrasing “All X are not Y”, we were told, is a traditional phrasing that is an artifact of its literal translation from the original Greek (or Latin?) wording, where the phrase is not ambiguous as it is in English.

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