Epistemology

[Pete]

Yes, that experiment would count as evidence for the speed of light in that specific scenario, as long as it could be verified again and again.

Actually it doesn't really prove that. One has to assume that space is isotropic. If one carries out this experiment than all that can be deduced is what is known in relativity circles as the two-way speed of light. That means that all you've been able to do is to measure the time the light takes to go there and back. Its concievable that the light goes faster than c in one direction and slower in the opposite, return, direction. Physicists have gone one step further and have measured the one-way speed of light. That's not as easy as it sounds so it took some time to create such an experiment. What happens is that two atomic clocks are synchronized at one place and one clock is moved to the another place rather slowly. Then signals from distant sources are used to demonstrate that the one-way speed of light is the same as the two-way speed of light. This might seem trivial to some people but its one of the things that physicists go to great lengths to make sure of. Experimentalists are awesome people. Very patient!

No I do not know that there is no evidence that God exists. I am an agnostic atheist, I claim no knowledge of God. Theists have it very easy. All they have to do to prove God exists is to find one piece of evidence confirming it. Then it doesn't matter if atheists keep "not finding" him in places, because he has been found. Theists have yet to find this one piece of evidence.

The point I was trying to make with my example was that what one actually has is experimental data. One has to interpret that data and the interpretation isn't always obvioius. For example; It used to be assumed that the decay rates of nuclei was a constant in time. Recent measurements have shown that there is a seasonal variation (rate changes with Sun-Earth distance) to the decay rates of a few isotopes (and probably applies to many more). So we have data and there is an interpretation. But one has to think about this very carefully and scientists have to do their best to think of other reasons for this variation in decay rate. One obvious reason is that the neutrino flux is larger when the Earth is closer to the Sun and this neutrino flux may be effecting the decay rate. So while nuclear physicists used to think they had evidence that the decay rate was constant it might be true that they made a mistake and the errors in observation were simply within the range of experimental error.

I can take things as true based on evidence or based on trusted processes. Just how I would trust my sister when she tells me that she needs some money, I trust the process of peer review. So yes, peer review could be seen as an authority, but it has worked so far so we have a level of trust.

Many people see E = mc^2 and assume its true. This means that they assume that its valid in all concievable situations. It turns out that is incorrect. There are instances where that relation does not hold. Einstein himself figured that out and a good relativist knows this. Its just one of those very little known facts that is rarely brought up. There have been many similar examples of these kinds of things in the past. When things become clearer it can sometimes lead to scientific revolution.

Here's another question - It is often said that Einstein proved that gravity is a curvature in spacetime. Almost all relativists nowadays will agree with that statement. My question - Is it true?

Another question: It is also often said that the mass of an object increases with speed. Is that true too?

These are obviously trick questions since I know the answers. But the answers are not obvious at all.

Pete