# Symbolic Logic Definition of an Opposite

**URL:** <https://www.thephilosophyforum.com/t/symbolic-logic-definition-of-an-opposite/3873>\
**Category:** Logic & Philosophy of Mathematics\
**Created:** [November 2, 2026, 7:26am UTC](https://www.thephilosophyforum.com/t/symbolic-logic-definition-of-an-opposite/3873 "2026-11-02T07:26:51Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![at1234](https://avatars.discourse-cdn.com/v4/letter/a/97f17d/32.png) [@at1234](https://www.thephilosophyforum.com/u/at1234)\
**Post date:** [November 2, 2026, 7:26am UTC](https://www.thephilosophyforum.com/t/symbolic-logic-definition-of-an-opposite/3873/1 "2026-11-02T07:26:51Z")

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Is it possible to give a logical/mathematical definition of what makes a something an opposite of something else?

Hot is considered the opposite of cold, light the opposite of darkness. But is upstairs the opposite of downstairs? Is cool the opposite of warm? And can “oppositeness” be described by a definition in symbolic logic?

Or is it just vibes?

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**Author:** ![Javi](https://yyz1.discourse-cdn.com/flex007/user_avatar/www.thephilosophyforum.com/javi/32/1673_2.png) [@Javi](https://www.thephilosophyforum.com/u/Javi)\
**Post date:** [November 2, 2026, 8:07am UTC](https://www.thephilosophyforum.com/t/symbolic-logic-definition-of-an-opposite/3873/2 "2026-11-02T08:07:43Z")

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> [@at1234](#):
>
> But is upstairs the opposite of downstairs?

That’s a very good question, indeed.

> [@at1234](#):
>
> can “oppositeness” be described by a definition in symbolic logic?

I don’t know because when I see symbolic logic as this, **¬𝑃** or this, **𝑃→¬𝑄** , I think it may be representing contradiction and not _oppositeness._

@Banno and @Michael may know.