How do you know unicorns do not exist?

[Simon]

Some people talking on the "santa" thread by dangerdan think they're really clever. I think they being completely irrational. They're not asking the right questions, and they're failing to understand something basic about Metaphysics and Epistemology. It reminds me of a conversation I had recently with a friend, about unicorns.

She asked me something like, "How do you know that unicorns don’t exist?" She was trying to make an argument for her unbelief in God. She wanted to say that it was reasonable not to believe in God, and that we have no reason to believe in God. She was attempting to show that it is unreasonable to think that God exists - that, perhaps, we have just as much reason to believe in unicorns as we do in God.

I offered another problem, that of other minds, as a better analogy to work with – I told her I thought that the problem of other minds is much closer to the issue of whether or not it is reasonable to believe that God exists. I think she remains unconvinced, however.

I quoted to her J.P. Moreland, who says it best these days: "Existence resides in the having of properties." Strictly speaking, I know that unicorns don't exist because there is no thing that has the property of being a unicorn. The statement, "Pegasus is a unicorn," is a real thing, a proposition, but it does not have the property of being a unicorn.

The next question is this - How do I know that there is no thing that has the property of being a unicorn? Well, this is easy because part of being a unicorn is the having of certain physical properties like horseness, one-hornedness and so forth. And, since that which is physical is observable using the 5-senses, and since I do not observe unicorns with my 5-senses, then I conclude that unicorns do not exist. This is not an argument from ignorance, because I am not ignorant in this area. Certainly if a unicorn existed I would have known by now; on top of that, certainly if a unicorn existed other people would know by now as well.

So, Unicorns, if they exist, have certain physical properties. I, along with every else, do not observe a thing having those physical properties. From that we can see that unicorns do not exist. The question of other minds is a different question because the mind is not thought (by most) to have physical properties.

Now, there is a question of whether or not a belief is justified (or warranted, to use Plantinga's preference). I think that even if I was the only person whose testimony was under consideration here, I would still be justified in thinking that unicorns do not exist - yes, because I have not seen a unicorn using my physical eyes. True, I reason that if such a thing existed, it would be known by other men - probably kept in some zoo or laboratory.

You ask, can't you then use the same kind of reasoning with respect to God? Well, remember the important difference here is that God is not thought to be a physical thing with physical properties. So, that I don't see Him with my physical eyes does not justify my not believing that He exists. Perhaps other information does. But certainly not the same kind of information that justifies my not believing that unicorns exist such as my not seeing with my physical eyes a unicorn.

My friend was surprised, I think, that I could claim to know that unicorns do not exist simply from the fact that I do not observe them. And she seemed to remain confused about why the same kind of "logic" doesn’t apply with respect to God.

"How can you say you ‘know’ that unicorns do not exist?" she wonders. Perhaps what she meant to convey by "know" is something more like "necessarily have undeniable proof that everyone else will accept".

In that case, no, I do not "know" (necessarily have undeniable proof that everyone else will accept) that unicorns do not exist.

But I was using the word "know" to convey in a statement, "this is how I know unicorns do not exist" something more like .. that which I believe to be justifiably true .. and in this case, certain criteria must be met - one of which, my perceiving with my 5 senses unicorns existing (since unicorns are said to be physically existing things, at least).

But she is correct in this respect: this criteria is not a sufficient reason for my believing that unicorns do not exist (I'm glad you explicitly made this point that I meant to implicitly make). Nevertheless, it is a necessary condition (and not so with regard to other minds or God, by definition - I assert).

If you say that "I think that God does not exist" (and by "think" you mean "necessarily have undeniable poof that everyone else will accept") because you don't experience Him physically or otherwise, then you can see how we may say that your logic is faulty.. in part because it is obvious that other people believe that God exists and or that they have experienced God in some way.

However, if you say, "I don't think that God exists" (and by "think" you mean "hold a belief that seems to me justifiably true") because you haven't experienced Him physically or otherwise, then I think your logic is valid insofar as it goes, but only insofar as you recognize that it may be the case that God's existence is not dependent on your experiencing Him in any way (but that that is a different question from whether or not you are justified in believing that He exists) and that it may be the case that your not experiencing God in any way is not a sufficient condition for justifying your unbelief. Perhaps it is a necessary condition.

The difference between the question of whether or not a unicorn exists and whether or not God exists is, of course, that while not having experienced either in any way may be a necessary condition for holding a justified belief that either does not exist – it is nevertheless not a sufficient condition; and moreover, the other necessary conditions needed to have a sufficient basis for unbelief in either will not be in the same ballpark, since in the case of the unicorn we have on the table the fact that unicorns are said to be things that, if they existed, would have physical properties measurable by the 5-senses whereas God, if He exists, would not.

[potwalloper.]

Simon wrote

Well, remember the important difference here is that God is not thought to be a physical thing with physical properties. So, that I don't see Him with my physical eyes does not justify my not believing that He exists. Perhaps other information does. But certainly not the same kind of information that justifies my not believing that unicorns exist such as my not seeing with my physical eyes a unicorn.

You appear to be saying that God is not a physical thing with physical properties.

If God is not a physical thing then God is either merely conceptual or God does not exist at all.

I can conceive of many things that lack physical properties but that does not mean that any argument may be made successfully to verify their existence any more than the existence of God can be verified in empirical terms.

That is the difference between imagination and reality...

...unless of course you are trying to say that God is not subject to physical laws and is beyond our understanding in which case I would have to use the Santa argument

[scorpia]

If one or more of the gods exist, shouldn't their existence be knowable outside of their associated scripture?

True, Mr muffin.

Then again, when I looked it up, does it not say 'seek, and you shall find?'. Nice bit of advice there... Maybe I could have figured that out myself ?????????????

[dangerdan]

If, because He is nonphysical, He is then “somewhat abstract, remarkably unverifiable, and as such, totally irrelevant” then you have to say the same things about love, numbers, thoughts, other minds, ones own mind, and everything else nonphysical.

You have raised an interesting issue. Very philosophical…I like it!

Love, etc, are concepts, not beings. People would not generally say that “concepts exist”. Otherwise nothing would really “not-exist”! Even our invisible unicorns would “exist as a concept”. When I say that God and invisible unicorns are irrelevant, it’s because they are meant to be beings.

By the way, what argument was Kant the first to solidify?

…the point that if something does not intervene with our sensory percepts, then we can’t really say much about it.

To repeat, the reason why invisible unicorns and God are irrelevant, is because any statements made about them are totally unverifiable. Actually, my philosophical daily quote was quite timely I thought –

In so far as a scientific statement speaks about reality, it must be falsifiable: and in so far as it is not falsifiable, it does not speak about reality.

Karl Popper
--The Logic of Scientific Discovery

[Dilettante]

I don't know if this has been mentioned already or not but, seeing a unicorn (or a photograph of one) would not be enough to establish the existence of unicorns.

James Randi famously said something like this (I'm quoting from memory, so the wording will be different), to justify his aggressive investigation of a French homeopathic lab's weird claims: If I told you I kept a goat in my backyard, all you would have to do to check the story is send someone and tell him to look over my fence. But If I told you I kept a unicorn in my backyard, would the same method be appropriate?

If some guy somewhere produced a unicorn, a team made up of the best zoologists and the best conjurors in the world should examine the beast before it could be authenticated. Why conjurors also? Because it is a hoax, scientists may not be as equipped to discover it as professional conjurors whose job is to make people belive the impossible. No hoaxer could beat them at their own game.

Still, one fake unicorn probably would not categorically "prove" no real unicorn could be found in the future (remember the story about black swans?). It's not easy to prove that a giant pink elephant is not orbiting
one of Saturn's moons. But we can safely assume that there is no danger of unicorns existing anytime soon. The horse's evolutionary line does not seem to point in that direction, at least.

[eveil42]

i belive what scorpia had said before about "maybe we just might not be able to detect something within our senses", reinforces the argument. also, just because we may not be able to see some thing with our primordial inner and outter stuctures, that does not mean that our senseses are not capable of perceiving something outside of our own existence. then again, the examples of santa and unicorns are ones that play on fiction. children for example belive in fiction. at times they belive to the point of truth or reality. does this mean that their understanding of something is not real or viable?