Do all concepts operate in pairs such that in order to define one member of the pair we need to specify its opposite ? For instance, we cannot define 'nothing' without understanding - being able to specify - 'something' and vice versa.

It is clear that not all concepts are explicitly members of pairs. But is polar opposition always needed even if analysis is needed in particular cases to discover what it is ?

'Opposition' includes not only a contrary or a contradictory but also and at least something which is distinctly different.

  • 1
    In short, yes. We live in a world of opposites. Indeed, it is often called this by those who propose that it is possible to escape from it.
    – user20253
    Commented Oct 23, 2017 at 10:58
  • A definition is a set. A set has an inside and an outside. The whole point of a definition is to create an opposition between what belongs to it and what does not. So yes, a definition requires its opposite, viz. the set of things that don't meet it.
    – user20253
    Commented Oct 31, 2017 at 12:44
  • 1
    I would say that a thing is defined by its properties. E.g. quantum particles are defined by their mass, charge, and quantum numbers. This set of numbers define a quantum particle. So I would define a thing in terms of its properties rather than as a measure of its amount of non-existence.
    – Nemo
    Commented Oct 31, 2017 at 20:06
  • YES! And this one of the most important observations in philosophy. Hence we live in a world of opposites. It is by reducing the polarities thyat we arrive at a fundamental theory. This is explained by George Spencer Brown in his 'Laws of Form', by FH Bradley in his 'Appearance and Reality' and by Nagarjuna in his 'Fundamental Wisdom', and is much discussed by kant and Hegel. .
    – user20253
    Commented May 4, 2020 at 14:45
  • There are at least five kinds of 'opposition' with different characteristics. complementarity, contrast, continuum, orthogonality and contradiction. So no, not even all kinds of opposition are polar, and things do not have single opposites. Is the opposite of a 'person' an animal, an alienated husk, an object, a crowd... Commented May 5, 2020 at 4:16

6 Answers 6


It depends on your point of view. You can define something by opposition, A=-B, but you can define positively A=B or tautologically A=A. Words are defined positively. In politics you have the same issue. Like Paul Sartre says in Critic of the Dialectical Reason the jew has defined himself firstly as opposed to the anti-Semitic.Then he defined himself through the figure of the State of Israel. And lastly, he defined himself by finding his singular character, by asserting his uniqueness.

In the case of the "nothing", you can have a purely logic concept who opposes to the being concept, or a more metaphisical concept (like medieval notion of nothing), where the nothing has it's own (no)-determinations in itself.

Kind regards.


This idea crops up in a number of different contexts in Modern Western Philosophy:

  1. In Hegels phenomenology he starts with the thesis Nothing whose antithesis is Being, and whose synthesis is Becoming.

  2. In Saussure linguistics, elements of language are understood not in terms of themselves but of their differences.

However there are many modes of definition - oppositional is only one, and they are not neccessarily mutually exclusive. Substance in Greek antiquity is positively defined by its characteristics, but also in opposition to Void. Substance is what is in common with what on the face of it are differences. The eternity of substance comes from the already existing idea of immortality of the gods.

In Nagarjunas Buddhist metaphysics, Being is Empty. So here we have a categorical difference in Western Metaphysics that is asserted to be equal. In fact, it is paradoxical in the strong sense of the word.

In Daoist metaphysics, definitions in the strict sense are not possible. For what can Be is always fuller than our means of description. And this is just as true of Nothing.

In Shurawardis Sufi metaphysics Being is light, and where light is not is Nothing; but light is not self-subsistent - it is an emanation from Allah - who is outside of Being and outside of Nothing.


I think this is related with the notion of entropy. If something is constant, necessary and omnipresent, it seems to be undefinable as there is nothing to compare it with. A constant, with no entropy, means no information and no knowledge, nothing to say about it.

However, we don't need the "opposite". What are the opposites between vacuum, water and air? What is the opposite of red? I think the best example is gravity.

Magnetism and electrical charges have two polarities, so the force can be attractive or repulsive. In quantum mechanics we can see a lot of symmetry, but gravity is puzzling because it seems not to be symmetric. Both matter and antimatter have the same gravity if I'm not mistaken.

However we have fairly good definitions for gravity. We have now gone to the space and we have a notion of "weightlessness", but:

  • there is gravity in space as well, although it's small and other forces like inertia may be more significant.
  • gravity was well defined before, we didn't need to go to the space to define it.

How could we study gravity before? Because it's not constant. For instance it is weaker in the mountains. Therefore we don't really need the opposite, but variability is definitively interesting and important. With a differential in gravity we can study it's causes, define gravity as dependent on those causes, etc.

If gravity was constant, like the speed of light, we could still know it and have some information about it, but the greater the entropy (contingency, variability, etc.) the more we can know about something.

  • In particle physics there is a property called color charge that can be anti-red.
    – Nemo
    Commented Oct 31, 2017 at 6:52
  • What do you mean by gravity not being symmetric?
    – Nemo
    Commented Oct 31, 2017 at 6:53
  • "Both matter and antimatter have the same gravity if I'm not mistaken". This is yet to be experimentally tested.
    – Nemo
    Commented Oct 31, 2017 at 6:55
  • YES! And this one of the most important observations in philosophy. Hence we live in a world of opposites. It is by reducing these polarities that we arrive at a fundamental theory. This is explained by George Spencer Brown in his 'Laws of Form', by FH Bradley in his 'Appearance and Reality' and by Nagarjuna in his 'Fundamental Wisdom', and is much discussed by Kant and Hegel. .
    – user20253
    Commented May 4, 2020 at 14:46

I believe it was Socrates who stated, "Asserting the existence of a thing also asserts the existence of its opposite." That is, if something exists, then it exists relative to and contrasting with something. It seems that this is the principle to which your author was referring.

But it is not necessarily true that the contrasting existence must exist concurrently with the other thing. For example, "nothing" in the quotation is contrasted with "something," but the concepts are just as contrasting when one follows the other chronologically, as when both exist side-by-side. There can be "nothing" in a cup, relative to the "something" you then pour into it.


You cannot perceive anything, if it is not relative. Perception itself based on the two polar system. If something is existed, you are comparing it with its non-existence. If you ask me the opposite of cat, I will say that both are coming to you simultaneously. (1) Its unidentified appearance (2) Its 'un appear able' identity. The image of cat cannot come alone. We have visibility and invisibility, both depends on each other. If there is no invisibility, you cannot view anything. Gravity can be felt only because the repulsion balances it. If there is no repulsion, the universe will come to the stage of Big Bang again.


Like you and @PeterJ mention,
set "A" => everything that is not "A"
some examples of set A are the first halves of the following:

  1. The north of a magnet implies its south.
  2. A thing implies everything-but-the-thing
  3. Me implies everyone-else-but-me
  4. We imply everyone-else-but-us
  5. Duality implies the non-dual

The underlying theme of the two poles i.e. the magnet is a singular concept.(well a magnet implies things which aren't a magnet , but we draw a boundary at the concept of a magnet for the sake of argument)

This is termed Advaita in the Hindu documents called the Upanishads.
Here dvaita(dual) implies A-dvaita(the non-dual)

The concept of Advaita is non-polar. Therefore not all concepts are polar.


  • Could you add detail to the term “Advaita”? A lot of readers are not going to know what this is. Commented May 4, 2020 at 19:01
  • Hi @MarkAndrews will it suffice to provide a link to Advaita on wikipedia? namely this. Please let me know if this isn't the right resolution to your comment in which case I will amend. Commented May 8, 2020 at 17:28
  • I suggest a sentence or two describing your understanding of Advaita, plus the Wikipedia link. Commented May 8, 2020 at 21:59

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