Quantum theory question?

Question

Long ago, Ptolemy had a theory of the cosmos with an accurate, yet incorrect, mathematical model for it. His version made assumptions that were inconceivable, because they were impossible. I have been told that quantum theory makes assumptions that seem ridiculous, but they must be true because the mathematical model is so incredibly accurate. What are these assumptions? Also, how do we know that it isn't the case that quantum theory is accurate, yet incorrect as the Ptolemic universe was?

I just want to clarify. I was only giving the Ptolemy example for illustration, I know it was wrong. My question is how can we trust that quantum theory correct and not just some really really really good mathematical model, that happens to be incorrect?

I am sorry, but I wasn't really satisfied with these answers. All I wanted to know was what were the strange assumptions quantum theory has to make, and how can we know quantum theory is an accurate model for the universe and not just some really good mathematical model. I didn't really want a lecture on Kepler or Einstein or determinism.

Answer 1

What a great question. I have thought the same thing. The answer at present is that we don't know. Quantum physics could very well be a whole lot of Ptolemaic empiricism, just waiting for a Copernicus to come and set us all straight. However, just like Ptolemy, the quantum physics that we now have does do a fairly good job of predicting and explaining what we observe, to a point.
I personally believe that the best argument in favor of quantum physics is that it explains why we are able to make choices, and it explains why we are absolutely unable to predict the future of something. Another way of putting it is that as we look smaller and smaller at particles and matter, it all dissolves into a grainy seething mass of chaos. Without this, everything we do and observe would all be predetermined. Likewise, it is impossible to measure anything precisely. All we can hope for is a higher and higher level of accuracy as a function of how much effort we put into our measurements. For instance, it has been determined that the Moon recedes from Earth at ~3.5 cm/year. It is impossible to know what this number is exactly, even if you could measure it at the subatomic level.
The great Physicist Richard Feynman once said, "If you think you understand quantum physics, you don't understand quantum physics. " This is because NOBODY understands quantum physics, not even the people who win Nobel prizes in its pursuit. I hope this helps.

Answer 2

Science nut you should give back the 2 points.
Quantum mechanics has reached a point where, atleast for now it is unprovable.
Certainly it is nice to see that the math is consistant but that does not mean it matches.
Most of the assumptions being made in brane,string and M theories will be untestable for the near term.
The best hope for any results in the near future will come from the Large Hadron Collider in Switzerland. There are predictions, based on the latest theories posted on arXive.org already.
Until some predictions prove out the theoretical physics people are swinging in the breeze.

Answer 3

Ptolemy's predictions were not as accurate as Quantum predictions have proven to be. Einstein dedicated himself to prove quantum theory wrong in the later half of his life, but was unable to do so. Einstein felt that the probability randomness inherent in the theory is at odd with how the universe should operate under a Creator. Einstein actually solidified the theory as Bohr ad others kept besting Einstein in thought experiments and debates on the matter.

However, "imagination is more important the knowledge," as Einstein states. So no one should take any theory as absolute truth. Einstein excelled at tackling so called truths and offering new and better explanations. Challenging the accepted norm is not in vain.

Answer 4

I personally think they are way out to lunch on some quantum theories, the only theory I like is string theory. One major theory is that if no one is looking at matter then it is in all possible states at once and is in as many universes as it takes, this theory pretty much sums up quantum theory (vaguely). Your second question is asking the same questions that many scientists have been asking for years but do not know for sure. After all that's why they are called theories. Its any ones guess and many are not satisfied with these theories, not even Einstein.

Answer 5

Ptolemy's model was adequate when astronomers only had crude instruments to determine planets' locations vs. time. Even then he had to fudge his data to fit the theory (really!). The superior instruments built by Tycho Brahe centuries later lead to Kepler's laws. Ptolemy's epicycles where quickly replaced at that point as the object of study. Likewise, if a better theory that Quantum Mechanics comes along that can explain things that QM cannot (like when there are strong gravitational effects), QM will be replaced so fast it will make your head spin.

Answer 6

The Ptolemaic theory didn't work; quantum theory does. As extended in quantum electrodynamics, it has produced predictions which differ from reality by only parts per trillion -- and it's hard to measure much closer than that. The primary assumptions that quantum theory makes is that quanta exist: there are smallest possible packets of light energy, sound energy, et cetera, and that these have both wave and particle characteristics: they are described by wave functions, which are responsible for the uncertainty principle: you cannot know both the position and momentum of a particle with arbitrarily high accuracy.