In Plato's The Sophist, a stranger from Elea argues with Theaetetus, a young friend of Socrates, about the definition of "sophist". They come to the conclusion that the sophist imitates the wise man. He gives the appearance of knowledge while actually being a purveyor of falsehood - but this gives rise to a paradox...

Stranger We are really, my dear friend, engaged in a very difficult investigation; for the matter of appearing and seeming, but not being, and of saying things, but not true ones—all this is now and always has been very perplexing. You see, Theaetetus, it is extremely difficult to understand how a man is to say or think that falsehood really exists and in saying this not be involved in contradiction.

Theaetetus Why?

Stranger This statement involves the bold assumption that not-being exists, for otherwise falsehood could not come into existence. But the great Parmenides, my boy, from the time when we were children to the end of his life, always protested against this and constantly repeated both in prose and in verse:

Never let this thought prevail, saith he, that not-being is; But keep your mind from this way of investigation.

So that is his testimony, and a reasonable examination of the statement itself would make it most absolutely clear. Let us then consider this matter first, if it's all the same to you.

(Plat. Soph. 236d-237b)

I understand this, simplified, as the step

Speaking what is not ⇒ speaking about non-being (S)

While the context here is resisting a Sophist opponent, who might come up with such arguments, this step (S) still seems like a mere word play to me.

How can (S) be made more plausible? Or can you recommend a commentary that focuses on this problem?

  • 2
    In a nutshell the issue is: if a statement must refer to reality in order to have meaning, what is the "reality" corresponding to a false statement? All the modern discussion about Truth is relevant. May 28, 2023 at 14:58
  • @MauroALLEGRANZA not enough. Examples or more context needed, add more meat to it, please.
    – viuser
    May 28, 2023 at 15:02
  • 3
    The argument goes by Quine's nickname Plato's beard:"Nonbeing must in some sense be, otherwise what is it that there is not". Russell's theory of descriptions gives a way of meaningfully using non-referring terms, and is taken as a modern refutation of the argument.
    – Conifold
    May 29, 2023 at 3:09
  • One main ancient context is Parmenides poem and the Eleatic Monists. plato.stanford.edu/entries/parmenides/#OveParPoe It’s closely aligned to there being only unity, no change. Here’s an undergrad lecture on the Parmenides poem youtube.com/watch?v=DsPnFPKnInQ&t=1224s
    – J Kusin
    May 29, 2023 at 13:51
  • @Conifold it reminded me of this, too, but Plato's argument seems a bit different. He doesn't conclude that non-being must be, but that non-being must have semantic content.
    – viuser
    May 29, 2023 at 19:31

4 Answers 4


As long as philosophers have been using words to correspond to things in the physical world, the question looms, what do words that do not correspond to things correspond to if we presume correspondence is what makes them meaningful to begin with?

Take the sentences:

  • A bird is a being.
  • A cat is a being.
  • A dog is a being.

Clearly, following use-mention, 'bird','cat', and 'dog' all refer to a class called 'being'. This is relatively straightforward. But after a dog dies, is the 'dog' now referring to a 'non-being' based on the claim that after death a dog is not a being? If the bird, cat, and dog all die, are they not non-beings since they are no longer in the class denoted by 'being'? 'Being' is a class with three examples: the bird, the cat, and the dog. And after they all die, they are not in the class 'being', and are now in the class 'not-being', right? So, if a being is a thing that exists, should a non-being be a thing that exists too? To some, the answer is yes.

But there are differences in actuality and appearance, and the stranger bids remind us of what Parmenides says about non-being:

Never let this thought prevail, saith he, that not-being is; But keep your mind from this way of investigation.

Why? Because, the appearance of non-being as physically existing is an illusion when we infer that three dead animals are non-beings in the same way that we infer that three live animals are beings. For beings exist since live animals exist, but non-beings don't exist even if dead animals do exist.

In more contemporary terms, though we can have a noun 'non-being' that functions like the noun 'being' and can be put in predicates in sentences in the same way, that doesn't mean that 'non-being' confers existence on its members in the same way 'being' confers existence upon its members. While 'A dog is a being' implies 'A dog exists', 'A dog is a non-being' does not imply 'A dog exists as a type of being, a not-dog' but rather 'A dog doesn't exist.'

These are all questions that arise in what is now called a correspondence theory of truth and probe the topic about what to do about words that don't correspond to the states of affairs. If they don't correspond to things in the world meaningfully, how is that they are meaningful at all? From WP:

In metaphysics and philosophy of language, the correspondence theory of truth states that the truth or falsity of a statement is determined only by how it relates to the world and whether it accurately describes (i.e., corresponds with) that world... Correspondence theories claim that true beliefs and true statements correspond to the actual state of affairs. This type of theory attempts to posit a relationship between thoughts or statements on one hand, and things or facts on the other.

It is therefore the accusation of sophism that non-being as a type of being is confusing and false word-play for properties of reality. This conversation foreshadows modern ontological discussion among men like Meinong, Carnap, and Quine where one might accuse Meinong of sophism in the same vein for positing Sosein and the Meinongian jungle. If you follow Parmenides advice, you may be interested in understanding the role of Nominalism in Metaphysics (SEP).


The seeming, is a seeming thing. The lie is not a non-thing, it also is what is. The appearance is what it appears. To say 'not-being is', makes a contradiction because it is an assertion of a negative, of an absence.

A mirage may confound because we take it to be water, but it always was what it was, and the mistake was in our evaluation, not 'in' it's existence.

You might like this answer: Why is a measured true value “TRUE”?

A counterpoint, on not-being as potentia, and being as self-assertion:

"love is the sea of not-being and there intellect drowns

this is not the Oxus River or some little creek this is the shoreless sea; here swimming ends always in drowning

a journey to the sea is horses and fodder and contrivance but at land’s end the footsteps vanish

you lift up your robe so as not to wet the hem; come! drown in this sea a thousand times

the moon passes over the ocean of non-being

droplets of spray tear loose and fall back on the cresting waves

a million galaxies are a little scum on that shoreless sea"

-from Subtle Degrees, by Rumi


Conversing about no-thing or non-being evokes the distinction between thing and no-thing or being and non-being. The distinction is something not no-thing. It is possible, but infrequent (very rare), to experience no-thing or absence of any particular thing or being as represented by items arising in the mind. But one cannot speak about this mystical state without evoking some sort of things in the mind. When the Buddha describes non-self as a mark of existence this always evokes my distinction between self and not-self and I wonder why he chooses the belief in not-self rather than the fact of self as the more persistent or real attribute of existence? I would conclude that self and not-self arise and pass away as distinctions along with concepts of what maps to reality or existence and what does not map to reality or existence. In the state that transcends distinctions there does not arise a map or relation of what exists or does not exist.


Two cents.

Where do lies live?

Obviously we can utter lies and literal nonsense. But how come we can form propositions that are lies, or falsehoods? How come they do not refer to something? Since they are lies and do not refer, how come they can be formed and uttered?

If we assume that an index in order to exist as an index it has to actually point to something that exists, then this becomes a tricky question. How come we can even refer to non-existent things? If an index points to nothing, nothing that exists, how can itself exist as an index?

Well maybe it does not exist as an index since it points to nothing but exists as something else. Then why on the surface it is so similar to real indexes?

On this point opinions differ.

Some take it that there can be indexes that exist but simply point to nothing.

Some take it that these are not real indexes, the resemblance is only on the surface.

Others take it that each index must point to something, thus the fact that the index points to nothing means that this nothing is a special kind of something that exists in its own way.


  1. Plato's beard
  2. Noneism

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