Question:
For example we take as granted that energy is conserved (Energy conservation Principle). Imagine someone “build” a theory where the energy conservation doesnt apply. Scientific community should reject this theory. But what if in the future conservation of energy doesnt apply ? Then the theory would be correct (assuming it predicts phenomena , is mathematic formulated etc.) ? I mean we reject or accept theories based on “axioms”. (It seems impossible to violate the energy conservation but we just have accepted).Does this mean that we are even doubt if a theory is right or wrong ?
Answer:
We (I mean, contemporary scientists) do not take for granted that energy is conserved. The energy conservation law came from observations and experiments. And we do not reject or accept theories based on “axioms”; we do/don’t do so based on the existing evidence. What's more, we always doubt that any currently accepted theory may be wrong. That’s why we always do a lot of various experiments to verify it (i.e., to see if it’s right or wrong).
Scientists nowadays use the method called “Scientific Method” (e.g., see ref 1 and ref 2) to find a theory that can account for the phenomenon in questions (see step 1 to 5 in the figure below).
Even if, such a theory (6) is found, continuing experiments and new evidence (7) can disprove it, and a new theory has to be found by beginning the process (2 to 5) again. So, any theory can never be guaranteed to stand forever un-disproved, not even the current thermodynamic theory, Einstein's Relativity theory, or the current quantum theory.
Question: Can a theory that is now wrong be right in the future?
Answer: Yes, it can. This is because the evidence that supports the theory may not exist or because poorly-collected/misinterpreted counter-evidence is found/presents at the time when the theory is proposed. The former case can happen because the evidence exists but has not been found yet or because the technology at the time is not advanced enough to find it. The latter case can happen because the method/technology to collect the evidence may not be correct or the required knowledge to interpret the result correctly does not exist yet. For example, in the 16th and 17th century the hypothesis that the earth revolved around the sun was proposed, but it was proved to be wrong at that time because
“… if the earth revolved around the sun then there should be changes in the relative positions of the stars over the year (see Stellar Parallax ). This stellar parallax could not be observed. Based on this and other 'facts', the scientists of the time were correct to reject the proposed hypothesis. What they did not know was that the stars were far more distant than they thought, billions of kilometres away instead of millions. Given the power of the telescopes of the time, they would not have been able to detect this parallax. ...”
The theory that the earth revolved around the sun was not proved to be correct until the eighteenth and nineteenth century when stellar parallax was finally observed. (from The Scientific Methods)
And, of course, a theory that is now right can prove to be wrong in the future. This is obvious from the figure above (i.e. when conflicting evidence to the theory is found - step 7). Real-life examples are several past theories that are now proved to be wrong, such as the theory that the earth is flat, the Aristotle’s theory of gravity (which states that objects fall at speed proportional to their mass), the theory of light that is exclusively corpuscular (such as Newton’s) or exclusively wave (such as Huygens’), a classical physical theory that holds that measurements of time and distance are absolute and not dependent on observers, and a classical physical theory that concludes that physical events can be definitely predicted.
