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Reddit
reddit.com › r/askphilosophy › is there an opposite to zero or is it inherently without opposite?
r/askphilosophy on Reddit: Is there an opposite to zero or is it inherently without opposite?
December 14, 2013 -

My girlfriend and I have discussed this a few times and can't quite decide if there is or not - we are definitely not philosophers.

Initially, we agree that zero is similar nothing and the opposite of nothing is everything. Therefore, infinity is the opposite of zero. But, looking at it numerically, you have negative (or a lack of) values. You could also say that a circumstantial "lack of" anything can be treated at a negative value.

But does this then mean that you could potentially say the opposite of infinity is actually negative infinity? Does this approach not put zero as the only non-value therefore meaning that it isn't even comparable?

At this point it gets a little deep for us, but our only other conclusion is that the opposite of 0 is actually 0. If this is the case, then is this the only example of this?

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If by "opposite" you mean "additive inverse" (as -1 is to 1, -2 is to 2, etc.), then 0 is its own opposite.

Initially, we agree that zero is similar nothing and the opposite of nothing is everything. Therefore, infinity is the opposite of zero.

I don't think there's any obvious sense in which infinity corresponds to "everything". There are infinite sets that don't contain everything, for example.

But does this then mean that you could potentially say the opposite of infinity is actually negative infinity?

You could say this is true about the surreal numbers:

https://en.wikipedia.org/wiki/Surreal_number

At this point it gets a little deep for us, but our only other conclusion is that the opposite of 0 is actually 0. If this is the case, then is this the only example of this?

As I said above, if by "opposite" you specifically mean "additive inverse", then 0 is its own opposite, and it's the only real number that has this property.

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I'd say "opposite" without further qualification or context is not really a well defined operation. Generally, by "opposite", I think we generally mean something like "reachable by reflecting on an axis of symmetry". But things frequently have multiple symmetries, meaning multiple potential opposites. Eg. we may consider the opposite of 2 to be -2 - if we reflect it through the origin, we get that value. But we might also consider the opposite to be 1/2 - it's multiplicative, rather than additive inverse. These symmetries may be context dependent - we could have different "origin points" that we're reflecting between. Eg. we might view "blue" to be the opposite of "red" if we pick the midpoint of human visible colours as our "point of reflection". But a scientist not attaching any special significance to visible light wouldn't see any reason to view wavelengths of 450nm to be the opposite of wavelengths of 620 nm? But we might also have other, culturally influenced reflection points (eg. "blue" may again be considered the opposite of "red" when viewed through the lens of "colours symbolising particular political viewpoints"). All in all, to speak of "the opposite" of something is to commit an error, in preassuming there could only be one such thing. That may be the case when you have a particular symmetry in mind, but you need to realise that this is what you're doing, and to discard that context is to change the question.

Ie opposites are properties of not just a thing on its own, but of that thing, a type of symmetry, and an axis of symmetry. Change any of those things, and you get different opposites.

In your case, you're looking at 0 using a particular "point of reflection" and symmetry in mind, but in that particular symmetry your point of reflection itself is the same as the point you're "reflecting", meaning 0 would indeed be its own opposite along that same additive symmetry. You can of course bring up different symmetries - but all those symmetries give rise to different "opposites" all the time - they're not just fallbacks for when one symmetry doesn't give you a good answer, making the other one the "real" opposite.

(And as an aside, in IEEE floating point maths, there are actually distinct 0 and -0 values, so in that context, the (additive) opposite of 0 would indeed be -0).

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CK-12 Foundation
ck12.org › all subjects › cbse math › overview of integers › what is a number and its opposite?
Flexi answers - What is a number and its opposite? | CK-12 Foundation
September 11, 2025 - The opposite of a number is the same distance from 0 on a number line as the original number but on the other side of 0.Zero is its own opposite because it is neither negative nor positive. Therefore, the opposite of 0 is 0.
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GeeksforGeeks
geeksforgeeks.org › mathematics › what-is-the-opposite-of-zero-in-math
What is the opposite of Zero in math? - GeeksforGeeks
December 7, 2021 - And, negative numbers like -1, -2, -3, -4 their opposite will be 1, 2, 3, 4 placed left from 0. All negative numbers have their opposite as the same numbers with positive value. Hence, the opposite of zero is itself.

number that, when added to the original number, yields zero

In mathematics, the additive inverse of an element x, denoted −x, is the element that when added to x, yields the additive identity. This additive identity is often the number 0 (zero), … Wikipedia
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Wikipedia
en.wikipedia.org › wiki › Additive_inverse
Additive inverse - Wikipedia
1 month ago - In mathematics, the additive inverse of an element x, denoted −x, is the element that when added to x, yields the additive identity. This additive identity is often the number 0 (zero), but it can also refer to a more generalized zero element. In elementary mathematics, the additive inverse ...
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courses.lumenlearning.com › wm-developmentalemporium › chapter › notation-and-definition-of-the-set-of-integers
Notation and Definition of the Set of Integers | Developmental Math Emporium
The opposite of a number is the number that is the same distance from zero on the number line, but on the opposite side of zero. ... 1. The number [latex]-7[/latex] is the same distance from [latex]0[/latex] as [latex]7[/latex], but on the opposite side of [latex]0[/latex]. So [latex]-7[/latex] ...
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Math Answers
math.answers.com › other-math › What_is_the_opposite_of_zero
What is the opposite of zero? - Answers
April 28, 2022 - Zero has no multiplicative opposite (or inverse). However, it has an additive inverse, and that is also zero, since 0 + 0 = 0 · The opposite value of a null set would be an infinite set, but infinity is not a real number.
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Study.com
study.com › math › basic math › mathematical notation
Opposite Integers & Absolute Value | Overview & Examples - Lesson | Study.com
March 5, 2015 - Let's see what happens when we add them up: 5 + (-5). When we have plus a negative number, it turns our problem into a subtraction problem. We have 5 - 5. What is that equal to? 0.
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quora.com › What-is-the-opposite-integer-of-0
What is the opposite integer of 0? - Quora
Answer (1 of 3): “Zero is Cosmic” when it comes to finding opposites (that is, it is the only number that exists for which its opposite is itself) “Four is Cosmic” when it comes to spelling (true for all integers) 13 (thirteen), for ...
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Open Space
openspace.infohio.org › courseware › lesson › 2064 › overview
Math, Grade 6, Rational Numbers, Opposite of a Number | INFOhio Open Space
The number 0 is the only number that is its own opposite. Whole numbers and the opposites of those numbers are all integers.
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thinktankscholar.com › pages › what-is-an-opposite-number-in-math
What is an opposite number in math? - Think Tank Scholar
0 · Your Cart is Empty · Login · Math Flash Cards · Sight Words Flash Cards · Preschool Flash Cards · Free Worksheets · Games · Awards · In math, an opposite number is the number on the other side of zero on the number line that is the same distance from zero.
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allinonehomeschool.com › opposites
Opposites – Easy Peasy All-in-One Homeschool
December 23, 2018 - The absolute values of opposite numbers are the same. Opposite numbers are equidistant from 0 on a number line.
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Combining Opposite Quantities to make 0 | sofatutor.com
Subtracting the opposite of -8, which is +8, from zero leaves you with -8. What is the result of adding +10 and its additive inverse? Adding +10 and its additive inverse, -10, results in 0 because they cancel each other out.