I think there is only one meaning of "exist". I think it means, has properties. So, for example, God exists means, Something is omnipotent, omniscient, all good etc. If that is true, then God exists. If that is false, then God does not exist.

Some questions:

1. Unicorns have properties (they have one horn; they feature in myths; they are often pictured, etc). Does this mean they exist?

2. Do properties have properties, and so on with an infinite regress? (E.g. does omnipotence have the property of absoluteness? Does beauty have the property of goodness?)

3. What about things with contradictory properties? Are they exceptions to your rule?

Some questions:

1. Unicorns have properties (they have one horn; they feature in myths; they are often pictured, etc). Does this mean they exist?

2. Do properties have properties, and so on with an infinite regress? (E.g. does omnipotence have the property of absoluteness? Does beauty have the property of goodness?)

3. What about things with contradictory properties? Are they exceptions to your rule?

Stories and paintings are representations alright, as memories are and perceptions too...

Unicorns have no properties. There is nothing to have properties. In stories about unicorns they have properties. And paintings of unicorns have properties. You are confusing stories and paintings of unicorns with unicorns. When we say that unicorns do not exist, we are saying that unicorn-properties belong to nothing. So how could unicorns have properties? So, whereas there are unicorn-properties, there are no unicorns.

ACB (pointing at a picture): Look, that's a unicorn.
Kennethamy: No it's not. There's no such thing.
ACB: What is it then?
Kennethamy: It's a picture of a unicorn.
ACB: A picture of a what?
Kennethamy: A unicorn.
ACB: But I thought you said there's no such thing!

The argument against your "narrow" criterion of existence is as follows. If there are no unicorns, then a unicorn is nothing. So a picture of a unicorn would be a picture of nothing, i.e. a blank picture. You might reply that it is a picture of unicorn-properties; but if a unicorn is nothing, unicorn-properties are nothing-properties, i.e. null properties, so we still end up with a picture of nothing!

Incidentally, I read an interesting article somewhere about what we might say if unicorn-like creatures were discovered on some distant planet. If the resemblance was close enough, would we regard them as "real" unicorns, or would we only regard them as unicorns in a figurative sense?

Whatever they are, they are not unicorns. Just as paintings of elephants are not elephants.

To what criteria does "real world" exist ? corpuscular theory is not even the only reference in the Science market...give me a brake ! To say that your vision is narrow is to say the least...you stand before an open system !

---------- Post added 10-24-2009 at 10:37 AM ----------

1. To say that something is real is just to say that it is not imaginary, or hallucinatory. As the American poet, Peter Vereck, put it, what is real is what remains after you have stopped believing in it.

2. But, I can certainly define the term "unicorn". "A white equine with a horn on its forehead, which has magical powers". Nothing fits that definition. Therefore, there are not unicorns. What made you think that I cannot define the word, "unicorn"? The word is in the dictionary.

No. I am not joking around at all. I am sure we will not be making anything magical, whatever we do. But, in any case, there certainly are no unicorns, since the is nothing that answer to the description, X is a unicorn. What might happen in the future has nothing whatever to do with that. In any case, from the fact that unicorns are logically possible, it does not follow that unicorns are physically or biologically possible.

...well that depends how do you look to Space\Time and Matter\Energy itself...

1- I consider that if it will exist, it already exists...(out of Time conception)

2- If you can recreate perfectly, Matter\Energy properties, in a given environment\World then is legitimate to say that its (the Unicorn) rational conception, that as i specified before, exists in a alternate\equivalent reality...anyway the point is not the Unicorn as you well know, but existence itself !

Regards>FILIPE DE ALBUQUERQUE

You have to Conceptualize existence in order to relate it to something, and establish some boundaries...the same goes for reality. Your vision to where i stand looks narrow...
Plus, you have to determine why there is no equivalence principle applicable to it, given the prior examples that I brought up before...

What does "conceptualize" mean?

I didn't say that something exists because it is real. Where did I say such a silly thing? What I did say was that when we say that X exists, we are saying that X has properties. Another way of saying it is that X exemplifies or instantiates certain properties. So, for example, to say that God exists is to say that something has the properties of being omnipotent, omniscient, all-good, and so on. If something has these properties, then God exists; if nothing has these properties, then God does not exist. And, of course, we may not know whether or not something has these properties. It is really very simple and clear what people mean when they say that something exists (or does not exist). They are saying that something has certain properties, depending on what they are talking about. What could be simpler? The question then arises (of course) whether it is true that something has those properties. Notice, I did not even mention the term, "real". Stubborness is irrelevant. If what I said about what "exists" means is wrong, then you have to show me why it is. And you have not.

I didn't say that something exists because it is real.

Properties are also subject to interpretation and limited in conception...properties are not Absolute for having or not having anything, not even to define whatever is there to be seen...for instance a Chemical property looks different through a Physics perspective, as it does from a Biological one... Al do they all may address the same issue, the fact is that they do it with a different scope ! And that changes comprehension of Phenomena around us...

But, so what? Nevertheless, what I say seems to be true. Everything "needs interpretation". But, that is not an objection to what I wrote. That, for instance, a chemical property and a physical property may "look" different. But if the property is sodium, it is the same property, however it "looks". So that makes no difference.