Plato's Beard

Magical Realist

Magical Realist

Valued Senior Member
A unicorn does not exist. But how can it not exist if it is not anything at all? Only something can not exist, right? Yet if it is something, it must therefore exist!

"In metaphysics, Plato's beard is a paradoxical argument dubbed by Willard Van Orman Quine in his 1948 paper "On What There Is". The phrase came to be identified as the philosophy of understanding something based on what does not exist.

Quine defined Plato's beard – and his reason for naming it so – in the following words:

This is the old Platonic riddle of nonbeing. Nonbeing must in some sense be, otherwise what is it that there is not? This tangled doctrine might be nicknamed Plato's beard; historically it has proved tough, frequently dulling the edge of Occam's razor.[2]
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The argument has been favored by prominent philosophers including Bertrand Russell, A. J. Ayer and C. J. F. Williams. Declaring that not p (¬p) cannot exist, one may be forced to abandon truisms such as negation and modus tollens. There are also variations to Quine's original, which included its application both to singular and general terms. Quine initially applied the doctrine to singular terms only before expanding it so that it covers general terms as well.

Karl Popper stated the inverse. "Only if Plato's beard is sufficiently tough, and tangled by many entities, can it be worth our while to use Ockham's razor."[5] Russell's theory of "singular descriptions", which clearly show "how we might meaningfully use seeming names without supposing that there be the entities allegedly named", is supposed to "detangle" Plato's beard."
 
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I looked up the standard definition of "unicorn" and it largely defined it as an imaginary or mythical horse with a single horn. But this doesn't really resolve our problem. Can an imaginary/mythical being even be such a horse? Horses we generally agree exist. But to be a unicorn is to not exist. How can a horse both exist and not exist at the same time?
 
Magical Realist said:
I'm not sure. Can non-existent things have meaning? What is "there" to have that meaning?
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Do existent things have meaning?


Pardon me if I proceed to say things you're already familiar with, MR, but we've never met, and I know nothing about your background.

In any discussion of this type it's absolutely vital at the outset to make a clear distinction between a word or a name, and its referent -- lest we find ourselves "proving" that 2 + 2 ≠ 4 !! (happened recently in another thread).

The distinction can be marked by using inverted commas or italics for the former, and regular font for the latter (or something similar).

Thus:

"table" or table or is a word or a name. It's a linguistic entity. It has five letters. And like other words it is meaningful, it has a meaning (or several).

A table is not a linguistic entity. It might be made of wood or metal, for example. It has no letters, and it has no meaning.

You'll find table in the dictionary, and learn its meaning if you don't know it already. You'll find a table in your living room.




So, getting back to your question at the top, what most of us would be inclined to say, I think, is something like the following:



The word table has meaning. It refers to real existent things: tables! The word has meaning; the referent does not.

The word unicorn has meaning; we can all understand what it means.. However, unlike table, it refers to nothing, or stated more precisely, it fails to refer. Unicorn is a non-referring term; it has no referent.



You'll get into a terrible mess if these distinctions are not marked. Trust me!

Also be aware, you're opening up the ultimate can of worms here: theories of reference! How does a word or a name refer to a thing/object/person, if indeed it does at all.
 
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To get you started, one popular theory of reference (cf. Frege, Russell) holds that a word or a name refers insofar as a description associated with that word or name is satisfied.

Theories of this type are known as descriptive theories of reference.

Thus, if the description (cf. definition) associated with the word "unicorn" is :"horse-like creature with a single horn" and nothing out there in reality satisfies this description, we conclude that the word fails to refer: there are no such things as unicorns.

Now, try it for "gravity" and see what happens.
 
Very interesting. It seems to me though with description we are still in this problem of reference to non-existent things. Can a non-existent thing be described? What exists such that it is even possible to describe? Maybe the description is of the word then. But is it the word "unicorn" that we are describing as an imaginary horse with a single horn? No. It is of the thing the word is still referring to. Description thus assumes this problematic referring function of the word to something, and in this case to something that doesn't exist. I have no idea how reference happens btw, even in the case with things that do exist. lol
 
Try the descriptive theory of reference for a word like atom too, say using a dictionary from the year 1800. The definition contained therein, based on the science of people such as Dalton, might look something like the following . . .

"An indivisible particle . . . "

We can stop right now! It is no longer believed that the word atom refers to an indivisible particle, Dalton's description -- just like our definition of unicorn -- is not satisfied (we believe). And on a descriptive theory of reference we conclude that Dalton's use of the word atom -- just like your use of the word unicorn -- fails to refer. There are no such things! -- as Dalton uses the word. His theory is quite literally a theory about nothing -- just like a theory of unicorns (cf. God).
 
Magical Realist said:
Can a non-existent thing be described? What exists such that it is even possible to describe? Maybe the description is of the word then. But is it the word that we are describing as an imaginary horse with a single horn? No. It is of the thing the word is still referring to. Description thus assumes this problematic referring function of the word to something, and in this case of something that doesn't exist.
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Perhaps a better, less self-contradictory, way to state the matter would be something like this:

We can offer a description associated with a word like unicorn. If that description is not satisfied, as far as we can tell at least, we conclude that the word unicorn fails to refer. It's a non-referring term. We conclude unicorns do not exist.
 
Thus stated, you're not describing unicorns themselves (they don't exist!). You're offering a description associated with the word "unicorn".
 
Sounds about right. But the very word "description", as being associated with the word "unicorn", seems to presuppose a something that is being described. Else why call it a description?
 
Magical Realist said:
Description thus assumes this problematic referring function of the word to something, and in this case to something that doesn't exist. I have no idea how reference happens btw, even in the case with things that do exist. lol
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You're quite right. Well spotted! With a typical subject-predicate statement such as "Dogs eat meat", we normally take this to be asserting both "there are dogs" and "they have the property of eating meat". We first assert their existence and then predicate something of them.

A statement such as "Unicorns don't exist" has exactly the same superficial structure. It therefore does appear to be asserting both "there are unicorns" and "they have the property of not existing" - a contradiction.

Frege, Russell et al warn us not to be misled. Superficial structure can be misleading as to what a statement is actually asserting. And they have their respective ways of analyzing the apparent contradiction away.
 
Magical Realist said:
Sounds about right. But the very word "description", as being associated with the word "unicorn", seems to presuppose a something that is being described. Else why call it a description?
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First, see above.

I don't see the presupposition you suggest. We can toss out descriptions willy-nilly. Some of them will be satisfied by something real out there; others won't.

Cf. "the highest prime number"
 
I cheated and looked up the definition of gravity. It's largely defined as the force of attraction between objects made of matter. But I know modern physicists have problems with calling it a force in the Newtonian sense. Does the word gravity refer to something that exists.? Maybe not.
 
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