Can you prove that self-contradictory things don't exist?

Question

I think so. I think you can prove that a round square doesn't exist. I think if anything can be shown to be self-contradictory, it can be proven not to exist.

You could say an object that is a square with rounded edges is a round square, but that object does not fit with the definition of a circle or a square so it is not an acceptable disproof.

Answer 1

Light is both a particle and a wave. Since these seem to be two different things (a wave is just propagation of energy with no definite boundary, while a particle seems to be a solid thing), then how can light be both?

===edit==

In response to "J.P." above, I am familiar with the quantum mechanical explanation, since I took physics in college too. It is similar to the argument that Christians use to explain how Christianity can be both a monotheistic religion and still believe in the trinity, but for some reason, atheists don't buy our argument because our description of God is something extraordinary that you don't see in everyday life. Atheists seem hypocritical in this regard, because they readily accept something complex and counter-intuitive like quantum mechanics, but not the trinity.

Answer 2

P&~P is false.

P...~P....P&~P
0...1.......0
1...0.......0


Self-Contradiction is false.

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Randy G:

It's not that it seems to be one or the other ... it's that it is both. It is a wave propagated by distinct force carriers (photons). In quantum physics, there's no distinction between particles and waves.

added:

Eh, you won't find me arguing Trinitarian doctrine. It made sense to me when I was a believer. I drew the same parallel you make -- if a quantum wave state can be both a particle and a wave simultaneously, why couldn't a unified deity be a triune deity.

You do have a valid point on this one. With great respect, that's kinda rare from you. This is a genuinely intelligent thought. I'm pleased.

Answer 3

With the caveat of using clear and precise definitions, I do not see how you can get around the law of non-contradiction.

On the other hand, proof of non-existence, depending on what you are defining proof as (for instance total and absolute knowledge versus presumptive evidence or logical proof), is more difficult than is proving the existence of something.

Answer 4

The simplest contradiction in terms I can think of is a boxing RING.