If existence is not a property, it seems that "existence" doesn't mean existing in our reality. If it meant existing in our reality, then surely speaking of "existence" as a property would make sense, such as saying, "Unicorns exist."

Rather, "existence" seems to mean we can conceive of the thing and we can discuss its properties. So, unicorns exist and we can speak about them, even though they are not part of our reality - we can conceive of them in some possible world.

Contradictions aren't part of any possible world, yet we can still conceive of them. We can discuss things like "square circles" even though no world could manifest them. And I wonder if this version of "existence" extends beyond possible worlds to include contradictions. One reason I think supports this is that we exist, and we can conceive of contradictions, so contradictions must exist, again, even though contradictions can't actually "exist" in the "unicorns exist" sense.

  • It would help a lot if you laid out a bit of the argument that existence is not a property, or gave a reference to where that argument is laid out. I've heard this in reference to the ontological argument, for example, but I don't know if that is what you mean.
    – philosodad
    Jan 7 at 3:02
  • If "there were" "no contradictions" , how could "there be": "being", "part", "any", "possible", ..."world", ...how could "there be" "no" (at all!?) ...unicorns/squares/circles? Without "contradiction", how could there be "any difference"?
    – xerx593
    Jan 7 at 9:25
  • If "contradiction not existed", there would be no difference between: -being/non-being, -part/whole, -any/none, -possible/impossible, -world/"non-world", me/not me...unicorns/squares/circles...
    – xerx593
    Jan 7 at 9:34
  • It would be worthwhile reading the SEP article on existence
    – Bumble
    Jan 7 at 14:00
  • On standard theory, existence is not a first order property, i.e. it is not a property of objects. But it is a second order property, a property of descriptions, which are, roughly, collections of predicates that (potentially) "describe" objects. For example, unicorn is described by predicates like "horse-like animal" and "with a horn", and we do not even need possible worlds to conceive of them. Contradictions exist in the same sense, there are contradictory collections of predicates, "plane figure, round and square", for example.
    – Conifold
    Jan 8 at 1:58

5 Answers 5


The reason some philosophers argue that existence is not a property is because in their metaphysics, a thing has to exist in order to have any properties at all. This would make an existence property somewhat circular because an object would have to exist in order to have the property of existence. Nevertheless philosophers of this opinion still think that existence is something that objects have; it is predicable of objects, but it a special category of predicable.

The question assumes

"existence" doesn't mean existing in our reality

but this does not follow from the claim that existence is not a property, nor from the metaphysics that lead to that claim. I'm not sure where it comes from, but since the whole question is based on that assumption, the only answer is that the assumption is wrong.

  • Thanks. If "existence" means in our reality and is a requirement for having properties, what about fictional objects and hypothetical objects? Don't they have properties? Also, what about universals/properties themselves? Don't universals exist even if they're not instantiated in our reality? And aren't universals/properties capable of having properties of their own?
    – th2o
    Jan 7 at 6:19
  • @th2o, there isn't any single answer to your additional questions; it varies from philosopher to philosopher. However, I think most who say existence is not a predicate would deny that fictional or hypothetical objects have properties. Jan 7 at 6:56

Your question is really about the meanings of the words we use. The word 'exist', for example, can be applied in different ways. My imaginary third foot exists as an idea, and can have imaginary properties such as an exquisite degree of opalescence apparent on the surface of the toenails. Clearly, when I say my third foot 'exists' as an idea, I am using the word to imply a different order of existence to that which applies to my real feet.

If you like, you are entitled to consider existence to be a property. However, you need to be clear about the different types of existence we have discussed. The sort of existence (1) which is a property of my imaginary third foot differs from the form of existence (2) which is a property of my real left foot.

Contradictions, such as a square circle or a car wasp, exist as ideas, so you can say they have the property of existence (1) but they do not have the property of existence (2). It is a matter of terminology.


The objective natural world is all made of real existing contradictions. This is the basic worldview of dialectical materialism.

Contradictions can exist in the objective world, but not in the way you may think of them. To take your example of the squared circle. It is evident and altogether true that a circle cannot have a squared form at the same time. To this kind of Contradiction in which the problem appears principally in the mind, Hegel calls it subjective contradictions. I can conceive anything contradictory I want using my subjective imagination and that does not mean they can or in fact exist in the objective world. The principle of no contradiction of formal logic definitely applies here.

But to understand the real contradictions in the objective world we must add a new dimensión: time and change. To use the squared circle example you could have a cake in the form of a circle and then cut it in the form of a square. It is the same cake but now it has changed form. It is a circle that turned into its opposite: a square. This is the type of objective contradiction that does exist in the world: things turning into their opposites through time and change.

This is dialectics and the whole world is built like this.


I would say the main problem here is assuming that we can actually conceive contradictions just because they might be objects of a sentence. Meinong played that card in his theory of objects, by claiming that we cannot know that there is no round square unless we make a judgement about the round square. The judgement does not actually give meaning to the notion of a round square or for any contradiction, on the contrary, the lack of meaning due to the mutual exclusivity of the constitutive terms of the contradictions is exactly what prohibits their meaning. The judgement can be understood, thus, as denying the conjunction of the main parts of a contradiction: affirmation of x, negation of x, and simultaneity. This is not understood by granting meaning to the whole and refuting it, but by analysing the meaning of each part and, through this, derive their necessary mutual exclusivity. An interesting analysis could also be applied to proofs by contradiction. When we assume ~A in order to derive a contradiction, we are not actually giving meaning to it, otherwise it would surely destroy the very purpose of the proof.

And in order to claim that if existence is not a property then existence is not "real existence", one must clarify what is meant by a property. I guess u could make an argument like this: If existence is not a property, it can be extended to include obviously non-existent beings. It cannot be extended to do such things. Therefore, existence is a property. That argument could work, but we must define what properties are. But to be honest, i do think that existence is being underestimated by those who claim that it is not a property, as tho it "doesnt add anything to the content of the thing which exists".


Items of recognition arise in the otherwise empty field of awareness. Some items of recognition arise as distinctions such as:

Exist, Not-Exist

Properties, Non-Properties

Contradiction, Non-Contradiction

There is a famous Zen koan (mind-problem) stated as this question:

Has the dog Buddha-Nature or not?

Before answering the question one must recognize the dog, Buddha-Nature, and the mapping of cognitive relations into concepts of Yes/No or True/False propositions.

In general all items of recognition exist as such. Language is recursive on the items of recognition, which include distinctions, arising in the populated field of awareness. Trying to discuss these insights evokes a semantic debate over the meaning of terms such as properties, attributes, etc. In the populated field of awareness everything that arises exists as an item of recognition until such items pass away in the stream of experience.

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