This is my first attempt at resolving this. I would have inserted some mathematical notation if it weren't such a pain.

All things that exist are a subset of the set of things that could exist. A subset of the things that don’t exist is contained in this set of things that could exist (the set of things that could exist but don’t), but those things that could not exist that don’t exist are not contained in the set of things that could exist. So, if we introduce things that could exist as such we would be adding an element to either the set of things that do exist or the set of things that don’t exist but could exist (or perhaps both). If we were to find the cardinality of the set of all of the things that could exist that do exist and subtract the cardinality of the things that could exist but don’t exist along with the cardinality of the set of things that don’t exist that could not from it, we get the net number of things that exist: if the number is positive, then there are more things that exist than don’t, and if it is negative, then more things don’t exist than do.

Leaning into your argument in the OP: when one introduces something that could exist, the possibility of it existing and not existing is introduced. This means that the state of affairs of it existing and not existing exist simultaneously in a sense. This means that when we add things to the set of things that could exist we get the same number of things that exist as don’t. They cancel out. However, this does not account for the things that don’t exist that couldn’t exist. These things, if they do indeed not exist, will always tip the balance in favor of there being more things that don’t exist than do. In fact, it would only take one such thing to do so.

Of course, one has to grant that the state of affairs of something not existing that might actually exist counts as something tangible enough in some way to be counted and that there are things that don't exist that couldn't exist.

Are there more things that exist or things that don’t exist? — QuixoticAgnostic

Oh, good, finally an easy one. If it doesn’t exist, it’s not a thing.

No further questions. I rest my case.

Would you not still be a thing if you could exist in a possible world in which you were cleverer? Are unicorns and goblins not things even though they don't really exist? Am I missing something?

Yes! I was going to bring up possible worlds. And Sherlock Holmes. Doesn't he exist in some fashion? What about undiscovered digits of Pi? Do those exist?

Yes! I was going to bring up possible worlds. — RogueAI

Nice.

Sherlock Holmes. Doesn't he exist in some fashion? — RogueAI

I would say so. He might exist under different interpretations in people's minds, but those interpretations come from a pretty much indisputable source (the books) that we can point to. So, in an abstract, behavior-guiding way I would say that he exists.

If all minds in the universe suddenly vanished, would Holmes still exist?

Every time I listen to my favorite deceased musicians' performances when they were alive, they reincarnate in my mind as if they were alive at present vividly. I often ask myself, do they actually exist in my mind when they are playing in the computer screens, putting out the powerful and great musical performance?

I am likely to believe they do, and they are part of my music listening life. But they have been physically dead for over 30+ or even 60+ years.

But there are folks I have never met or known living somewhere in the world doing their daily business right now. Do I have to convince myself that they exist? I don't know anything about them, and they don't know anything about me. It is only my imagination that that this is the case. Now which beings exist more realistic to me here? The dead or alive?

This implies we might have to take into account of different type existences i.e things that exist as visible, tangible, solid and accessible, and things that exist (or believed to exist), which are invisible, intangible, abstract, inaccessible and immaterial.

Are unicorns and goblins not things even though they don't really exist? — ToothyMaw

What’s the difference between “existing” and “really existing?” Maybe the title of this thread should be “Are there more things that really exist or things that don’t really exist?”

Anyway, of course goblins and unicorns exist. Or do only the ideas of goblins and unicorns exist? Or the words “goblin” and “unicorn?”

Or maybe it should be titled “Are there more things that are really things that exist or things that are really things that don’t exist?”

"exist spatially"? Then first response is right.

"exist conceptually"? Then definitely more that do not exist, in fact exist. See. Philosophy can be fun.

Q: Which has more legs, a horse or no horse?
A: No horse, because a horse has four legs, but no horse has five legs.

You are confusing yourself. I'm just saying that goblins and unicorns probably only exist as concepts, although they are familiar enough that we can clearly conceive of them as objects similar to horses or whatever might be analogous to goblins, even if they have to exist in the context of a world different from our own - probably in some fantastical, impossible way. I don't see why you would disagree with that. I mean, unicorns and goblins are usually magical or something, and I don't see you committing to the existence of magic to underpin and/or validate any of your other philosophical views.

You are confusing yourself. — ToothyMaw

I’m not confused.

a horse has four legs, but no horse has five legs. — Patterner

This is wrong. It’s my understanding that no horse has 10 legs.

This generated some interesting responses lol.

Anyway, of course goblins and unicorns exist. Or do only the ideas of goblins and unicorns exist? Or the words “goblin” and “unicorn?” — T Clark

I can't tell if you're being facetious or not, since it seems counter to your initial sentiment, although it is logically consistent.

If a "thing" doesn't exist, then it's not actually a thing. So I take it we're actually failing to refer to anything at all by "thing". That does seem to commit us in some way to saying "If we can refer to something, then it must exist", like your goblins and unicorns. But as you note, these exist in a particular way, i.e. as ideas rather than physical entities.

That said, I think we can identify different classes of non-existent "things". The first is that which cannot be referred to; when I claim to talk about a "thing", but my utterance is effectively gibberish. But another is impossible objects, i.e. contradictions which are in reference to existing things. For example, the integer k between 1 and 2. We can say 1 and 2 are things that exist, but the proposed object k does not. The question is, is k a thing despite not existing, or is it the same as that which can't be referred to? I guess it's just the latter...

Anyway another thing that crossed my mind is how this question relates to a similar question: "Are there more true claims or false claims about the world?" This seems a little more vague, because while existent things may be finite, it seems truth claims can be arbitrarily infinite. Food for thought...