# Inverting the laws of physics [closed]

Are there any good theories on inverting the law of physics?

To make physics work the opposite way of what it does.

Ok, I'll try to explain better. I was taking a smoke break and started thinking about time travel, and somehow I concluded that to travel in time itself is impossible.

But then I thought that, what if we instead of travel in time, could reverse all processes in the world, or in an area for example. To make all particles do all what they have already done, but in reversed order.

i.ex. A candlelight produces heat and light emitting from the flame, the candle itself melts and turns into vapor.

If we reverse that, all the heat, vapor and light would be absorbed by its origin point and reassemble the candle the way it was.

Damn this is hard to explain. And there are so many holes in what I'm thinking here.

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## closed as unclear what you're asking by Emilio Pisanty, Chris White, BebopButUnsteady, Waffle's Crazy Peanut, DanAug 26 '13 at 21:05

Please clarify your specific problem or add additional details to highlight exactly what you need. As it's currently written, it’s hard to tell exactly what you're asking. See the How to Ask page for help clarifying this question.If this question can be reworded to fit the rules in the help center, please edit the question.

Just in case you didn't see my response in the flag feedback: use physics.stackexchange.com/contact. – David Z Apr 30 '15 at 12:10

I suppose that what you are thinking about is the principle of causality.

We have two events: a cause and an effect, where the second event is a consequence of the first. That is how we perceive all events around us and what we intuitively accept as true.

In physics, however, we sometimes obtain two different solutions: first with the cause before the effect, second with the effect before the cause (such solutions come, for example, when deriving potentials dependent on time in electromagnetics). You could say that the second one reverse the arrow of time. Indeed, there is no reason other than the principle of causality to discard this solution (when time flow backwards), but this is what is usually done.

Interestingly, lack of that principle would suggest that we don't have free will and the universe is deterministic.

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Now that your question is a little more clear I believe that the answer is no.

What you say cannot be done spontaneously (entropy variation should be >0).

You can reverse some things in some systems, but not everything.

I don't know if this what you mean but maybe this can help: http://en.wikipedia.org/wiki/Spontaneous_process http://en.wikipedia.org/wiki/Entropy

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