Impossibility

Excerpt from "Alice in Wonderland" (Lewis Caroll):
"There is no use in trying," said Alice; "one can't believe impossible things."

"I dare say you haven't had much practice," said the Queen. "When I was your age, I always did it for half an hour a day. Why, sometimes I've believed as many as six impossible things before breakfast".

What is impossible?
As human beings, we consider many things to be impossible. Some things we even use as metaphors for things which may never happen - like flying pigs. But why is it that we can still imagine pigs flying around?

What is real?
We like to think that we know the truth about things, and that these truths explain what we see around us. The speed of light, for example, has been considered to be a true and eternal measure.

Yet new research has shown that the speed of light may have changed during the age of the universe. And so may the expansion of the universe, which astronomers now claim may in fact be constantly increasing.

Although we can observe many things around is, we cannot know everything about what we see. We can't see beyond the edge of the universe, simply because all the light we can see comes from inside it. Or does it? How can we be sure of that?

On the other end of things, there is a limit to how small things can be in the universe. This is called a Planck length, after the physicist Max Planck. It is estimated to be 10^-33 centimeters. Anything smaller than this has no meaning in the physical world.

If I can think of something, is it true?
For some philosophers, all things that can be seen, must be real. But what does this say about things like "impossible" objects depicted by artists and painters? And what happens if I think about things which are smaller than the Planck length?

The answer may be that you won't, because you can't. But is it true?

Other philosophers claim that all things which can be imagined, must be real. If you can think of flying pigs, then flying pigs are for real. But this does not necessarily mean that they exist in flesh and blood, only that the "concept" of flying pigs is a "valid" concept. Get it? It is at least a great way to think if you have problems proving a theory...

Or, as the mathematical philosopher Kurt G?del once said, "The meaning of the world is the separation of wish and fact".

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