---------- Post added 02-25-2010 at 11:29 AM ----------

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---------- Post added 02-25-2010 at 12:00 PM ----------

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Only if words refer to something, then they refer to something that exists. But it is not true that words always refer to something. Therefore, they need not refer to anything that exists.

"The Spaghetti Monster" does not refer to any concept. It does not refer to anything. But, if it did refer to something, it would refer to the Spaghetti Monster. Of course, it does not, since there is no SM. I think you are confusing the term, "The Concept of the Spaghetti Monster", with the term, "The Spaghetti Monster". The term, "The concept of The Spaghetti Monster" refers to the concept of the Spaghetti Monster. But the term, "The Spaghetti Monster" does not refer to the concept of the Spaghetti Monster. It fails to refer to anything.

I don't know what "absolutely" is supposed to add, but, as I said, when a term has no referent, it fails to refer. That should be obvious. What "base principle" do you mean?

Whose law is that? I suppose by the first "something" you mean a term, or a word). Objects are not symbols, so they cannot refer. They are what are referred to.

Yes. We can know that there are no round squares.

Yes. We know this for a variety of reasons. First of all, things that are invisible are still detectable. We can detect air that is invisible to us. Second, an invisible unicorn would be problematic from the standpoint of the possible materials that it could be, and from the fact that eyes require non-invisible parts in order to function.

Now, if you go further, and start to ask about something that is not detectable in any way, then I will respond with saying that you are really and literally talking about nothing.

If by "unicorn", you mean a horselike animal with a single horn, then we do not know if any such things exist on a remote planet. But we do know that they do not exist here. By "we", of course, I do not mean absolutely every person, as some people are stupid, crazy, ignorant, and/or other things that may prevent them from knowing such things. There are people with silly beliefs who ought to know better, but they do not. But as far as what life, if any, exists on remote planets, we are not in a position to say much about it, unless the proposed thing is impossible.

We do know that no visible unicorns exist on earth, but we don't know that an invisible unicorn that makes no noise and is light as a feather doesn't exist.

If we know there are no unicorns, then we know that there are no invisible unicorns.

All knowledge is also belief. We cannot know something unless we also believe it. But knowledge is not only a matter of belief, it is a matter of true belief, and it is a matter of justified belief. Why wouldn't you think that we have true justified belief that there are no unicorns?

But do we just know (no italics) it? If not, why do you think we do not?

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If a claim is unverifiable then it is meaningless as a proposition and should be rejected on those grounds, but that doesn't mean that we know that what is being proposed doesn't exist.
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How do we know that there are no visible unicorns in the universe and how would that imply that there are no invisible ones?



I understand that all knowledge entails belief, but not all belief entails knowledge. I think that we don't have justified true belief that there are no unicorns (visible and invisible) because there's no way to verify that there are no unicorns (visible and invisible) in the entire universe. I think that it's a meaningless proposition.

If it is meaningless, then it does not refer to anything, so there is nothing that is even being proposed as existing. And we can know that.

It is meaningless as a proposition simply because it cannot be proven to be true or false, not because it refers to nothing (note that the notion of nothing can be very ambiguous). It's not that something isn't being proposed as existing. It's that what's being proposed is unverifiable and should therefore be rejected. This rejection is a statement of belief not knowledge.

Can we ever be positively (not absolutely) certain that any particular thing doesn't exist?

We know that there are no unicorns, visible or invisible because unicorns are supposed to be magical beasts, and we know there are no magical beasts. Of course, the existence of unicorns would be inconsistent with the laws of biology as we know them. How could they have evolved, and from what. What kind of DNA would they have? But I asked you why you think we do not know there are no unicorns. Don't you think that our believe that there are no unicorns is justified. Or that it isn't true? You must have some reason for thinking that we do not know there are not unicorns.

Why don't you think that our belief that there are no unicorns is true? Have you some reason for thinking there are unicorns? Or, don't you think that our belief that there are no unicorns is adequately justified? I suppose it is logically possible that there are unicorns somewhere in the universe. But why would that show we do not know there are none? It is logically possible the Sun will not rise tomorrow. But I believe I know it will. Unless your principle is that if ~P is logically possible, than P cannot be known. But why would you adopt that principle?

I agree that the proposition that there are no unicorns in all the universe is pretty vague, but not vague enough to be meaningless. Isn't it either true or false? And if it is, then it cannot be meaningless.

I don't think that anyone can now prove that there are extra-terrestrials is true or is false. But I don't think that astrophysicists think the proposition that there are are (or are not) is meaningless.

I think that our belief that there are no unicorns is justified, but I don't think it can be proven to be true or false. This is what makes it meaningless as a proposition. A sentence states no proposition if it cannot be proven to be true or false. I don't know that the sun will rise tomorrow, but I believe that it will.

---------- Post added 02-26-2010 at 08:51 AM ----------



If someone were to say that "extra-terrestrials do exist" it would be meaningless as a proposition if it could not be proven to be true or false. It would, however, be a meaningful question for some people.

I guess the problem is that I don't understand how you can call a sentence in perfectly good English that any English speaker can understand (even children) meaningless. You must mean by "meaningless" something other than "cannot be understood".

Could you also explain what is the difference between being justified and being proven true or false? I think you may mean by "being proven true or false" that if something is proven in that way, it would be impossible for it to be false. But what does that mean? In what sense of "impossible"?

I said that if a sentence cannot be proven to be true or false then it is meaningless as a proposition. In other words, it serves no function as a proposition. I'm not saying that it's meaningless in the sense that we cannot understand the meaning of the words.



When something is justified it means that it is based on sound reasoning. However I'm an empiricist positivist, and so reason doesn't equate to knowledge or truth in my eyes when dealing with a synthetic proposition.

The positivists meant by calling a sentence meaningless that the sentence had no truth value, not that it could not be proven true, since a sentence may have truth value and not be provably true. Like the sentence, "ETs exist".

When something is justified it means that it is based on sound reasoning. However I'm an empiricist positivist, and so reason doesn't equate to knowledge or truth in my eyes when dealing with a synthetic proposition.