What does it mean to exist?

Are you content with the question as you have formed it?

What does it mean to exist?

Compare:

What does it mean to garden?

What does it mean to play chess?

What does it mean to help someone in need?

What does it mean to suffer?

What does it mean to kill someone?

Compare the last question with the even more serious, 'What does it really mean to kill someone?' One can perhaps accept this as a question without knowing what its full import is. Perhaps it is a desperate expression of remorse and the wish to make amends. But this cannot be true of 'What is the meaning of gardening?' unless it means something tame, though not therefore unimportant, like, 'How does gardening contribute to your life?' Or perhaps you believe that you have wasted your life gardening, and you are now reflecting on this sad fact, if it is one.

It seems to me, without complete conviction, that the six questions shouldn't be attacked head-on. It really is pretty unclear what they mean and how they work (Cf. obviously, 'What does 'to garden' mean?' asked by someone, speaking in a foreign language perhaps, who doesn't know the English verb. This is very probably a request for a bit of translation. The answer might be, 'Look in the dictionary.' Or it might be to give the foreign language equivalent.)

Perhaps you have something in mind like, 'What is the yield of existence?' (But then this cannot be quite like, 'What is the yield of suffering?') The question becomes, 'What difference, if you like, does my existence on this planet (as opposed to some other?) make?' Or 'What difference does my existence on no matter what planet make?' You might think of the differences it makes to your friends, family, society, or even to God. Or you might simply be reflecting on the fact of your existence, as it were adding up a sum: I did this, I did that, I changed the other thing, and so on.

What difference does existence as a whole make (the existence of everything, everything to which the answer to the question, 'Does it exist?' is affirmative)? Well, all the difference in the world, or all the differences! (Kant didn't realize this.)

I agree with Jonathan Westphal that there's no simple answer to your question as you pose it.

One (no doubt overly simpleminded) way to approach an answer to the question is to make a list of things that exist and then see if they have any properties in common. But what would you put on this list?

You could think of beginning with a list of all of the kinds of individual things that exist: There are people, there are plants, there are animals, etc. That's going to be a pretty long list, but do these kinds of things really exist? Or is it better to say that only individual things of these kinds exist? So, instead, you should list all the individual people (Adam, Eve, Cain, Abel, ..., you, me), list all the plants (the rose on my desk, the rose on your desk, etc.), list all the animals (my pet cat Bella, your pet dog Fido, etc.). That's going to be an even longer list.

But are there such things? Consider any physical object. We know from physics that it's not really a single thing, but a complex thing consisting of atoms. But we also know from nuclear physics that it's really an even more complex thing that consists of quarks (etc.). So maybe people don't exist, only complexes consisting of quarks and other ultimate subatomic particles. (See Peter Unger's essay "Why There Are No People", Midwest Studies in Philosophy 4 (1979).)

What about artifacts like tables or chairs? Do they exist in addition to such "natural kinds" as people, plants, animals, etc.? They, too, are such complexes of subatomic particles. But even if you want to consider all ordinary, medium-sized spatio-temporal objects as being the kinds of things that exist (instead of just the subatomic particles), artifacts depend on their users for their existence in the sense that something is a table if and only if someone uses it as a table. So, a suitably sturdy cardboard box or a flattened tree trunk could (also) be a table. So, maybe tables don't exist in addition to things like flattened tree trunks.

Instead of making a list (technically called an "ontology") of things, or kinds of things, that exist, you could give a criterion for existence. Two of the most famous are:

(1) Bishop Berkeley's proposal that to be (or to exist) is to be perceived (this is the source of the famous "if a tree falls in a forest and no one hears it, then it doesn't make a sound"): If x exists, then someone perceives x (and that someone might have to be God, just in case no human or animal perceives x but you want to maintain that x exists); and if someone perceives x, then x exists (but then what about dreams and hallucinations?).

(2) Willard Van Orman Quine's proposal that to be (or to exist) is to be the value of a bound variable. In other words, any theory (e.g., a scientific theory expressed in a language for first-order logic with variables and quantifiers) that says "there exists an x such that..." is committed to the existence of such x's. (See Quine's essay "On What There Is".)

For more on these topics, look at the articles in the Stanford Encyclopedia of Philosophy on "Existence", "Metaphysics", and "Logic and Ontology".

Read another response by Jonathan Westphal, William Rapaport
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