I am currently trying to work out what on earth existence is. Not in a Descartes kinda way, but more 'is
existence a predicate' or in other words why is 'John is bald' any different to 'John exists'? Surely
existence is necessary for John to be bald. If I follow this through, can things which to not exist have
properties? Is it just a problem of defining existence (if this can be done) because things that are not
and have never been physical can have attached qualities (e.g. imaginary friends, unicorns, aliens).
I agree with your sense of bafflement. I do not see any difference between saying that John is bald,
and saying that John is(something or other). To be, is to be something or other, to have some
property, to be an object thought about, or talked about, or believed in, or imagined. Why do
philosophers insist on saying that existence itself cannot be a property?
There are historical reasons, to do with Kant's objections to the ontological argument for the existence
of God. Then there is the groundbreaking work in mathematical logic around the turn of the
nineteenth century by Gottlob Frege, who defined a second-order existence 'quantifier' as a property,
not of objects, but of concepts. But this is all a red herring, so far we are concerned.
Let me define a property 'Q' in the following way:
If any object x has a property F, then it has Q.
What is it to be Q? We can think of Q as the property of being something or other. Every object, by
definition, has Q. You and I have Q. imaginary friends, unicorns and aliens have Q. You'd think that
this is hardly news, to told that some thing has property Q, and you would be right. For the message
has already been gotten across when we used whatever referring expression we used to talk about
the thing in question.
The definition I have just given of 'Q' is a definition which does perfectly well for 'exists'. Philosophers
of language can argue about whether in ordinary language when we say that something exists, what
we 'mean' is the existence property, or the Fregean second-order quantifier. I would argue that there
is no fact of the matter here.
However, if we agree to talk about existence as a property of objects, we have to guard against a
fallacy. For we are tempted to reason as follows. "Things can go into or come out of existence. We
can think that a thing exists, and then it turns out that it doesn't exist, or think that a thing doesn't
exist, and then it turns out that it does exist. When we use 'exist' in this context, we must mean
something different from the mere property of 'being' something-or-other, which anything can have
whether it reallyexists, or not. It follows that there must be another property, real existencewhich
some 'existing' things possess and others do not."
If I say, "King Charles I" no longer exists, the object of my reference is not some shadowy entity, the
idea of King Charles in this or that person's mind, but the actual King Charles who wasKing of
England. One and the same objectcannot at one time be solid and real and at another time
insubstantial and unreal. There are ideas in people's minds, and there are physical things in the
world, just as there arefictional characters, mythical creatures, numbers and anything else one cares
to name. It is no less absurd to suppose that a 'real' King Charles could become an 'unreal' idea or
memory or concept of King Charles, than it is to suppose that the 'real' King Charles could become a
fictional character, or a mythical creature, or a number.