Originally posted by Bosse de Nage
What do you mean by 'identifying some impossible things'?
I think we are fairly sure that faster than light space travel is impossible. There is still a possibility of 'worm holes' and other ideas, so I wont rule it out altogether. But if you said you could make matter without using any energy, or better yet make a perpetual motion machine, I would not believe you whether you were alien or not.
All the Aztecs were thrown by the horses because they lacked any reference point to deal with it. That is my point: they were helpless before them because they couldn't name them.
Or so it was recorded. I rather doubt that it was as simple as that. It is far more likely that the Aztecs simply did not know what methods to use against them - as has been the case in many wars throughout history. Someone comes up with a new brilliant strategy / weapon and wipes out his opponent with ease until someone else comes up with a counter - or even better strategy / weapon.
It is entirely possible that the Aztecs saw them as somewhat God-like and feared the unknown, but that does not translate into "they were helpless before them because they couldn't name them."
I don't see why we should limit ourselves to the two possibilities that you suggest, which aren't even possibilities in our frame of reference because aliens, interstellar space travel and telepathy machines are all fantasies to date -- unless you have any evidence for their existence? Calculating the probability of a fantasy materialising seems somewhat fruitless ...
We shouldn't limit ourselves, but that only reduces the probability of aliens does it not? I only created the two alternatives to show him that he was being irrational about choosing the one alternative when I could show there was at least one other alternative that was more likely.
Anyway, I'm more interested in knowing why you disagree with Arthur C. Clarke.
Its a tough one. Maybe I do agree with him depending on how it is interpreted. I believe some things would appear to be magic, but that does not mean I think that the impossible would become possible just because technology advanced far enough. I think even if something appeared to be magic, we could determine whether or not it is possible. I actually think that a telepathy machine cannot be ruled out as impossible as we know enough about human minds to know that they can be manipulated with electrical impulses - so all that remains is a) knowledge of what impulses to give and where, and a means of applying the impulses remotely (again theoretically possible.) But a perpetual motion machine? Not going to happen.
On a side note: magnetism seems magical to me. I know we know what rules govern it, but we don't really understand what causes it, and when you see it in action it is quite amazing. I have a toy with a spinning top that you spin about 1cm above a base plate. It floats, spinning in the air and you can even pass your hand underneath it and it wont move.