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Can the laws of physics change from time to time or place to place? My argument is that they can't, simply by definition. Because, by definition, the laws of physics are statements which hold true everywhere and everywhen. It is a bit like how gravity has different strengths on Earth versus the Moon, but that is merely an environmental difference. So, if things are radically different elsewhere, that would again merely be an environmental difference, and it would also mean that what we thought of as laws of physics, were in fact environmental contingencies. Is this true, or can there in fact be different laws of physics elsewhere? And have any philosophers talked about this?

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  • Do you have an example of a specific law of physics that you are asking about the possible variance of? Like, "There are no uranium spheres past a certain diameter," maybe? Apr 11 at 16:19
  • Well, they could, but that change would be part of the law. For example, you have electro-magnetic fields that vary with time and place. Universe with varying speed of light in vacuum could be imagined.
    – rs.29
    Apr 11 at 21:35
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    Yes. Laws of physics need not be universal, i.e. hold true everywhere and forever. Indeed, all historically known laws have a limited scope. For example, the laws of classical mechanics only hold for small velocities and macroscopic objects, the laws of thermodynamics only hold for statistically large systems and only on average, the laws of general relativity and quantum mechanics are expected to be limited by quantum gravity, etc. The values of constants from fundamental laws may turn out to be varying in time, etc.
    – Conifold
    Apr 12 at 4:46
  • This question seems to be asking whether the laws of physics are logically necessary.
    – Geremia
    Apr 25 at 22:37
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Here is why that scenario is unlikely.

First we take the case of what are called conservation laws. These are book-keeping rules which are used to keep tabs on what's entering in, exiting out, and accumulating inside a system under study. By analogy with money in your pocket, you can see that the units in which the book-keeping is done may vary from place to place (pounds, euros, francs, dollars, yen, etc.) but the fundamental rules (you can't remove more money from your pocket than was there to start with) still apply. If that rule was false, it indicates the presence of a cheat by which the rules can be avoided (oboy, free money from out of my pocket!), and the system then collapses. Mother Nature might bat last, but you can't cheat her in any universe that is real.

Next we take the case of laws that are derived from facts of geometry- for example, the idea that the brightness of an incoherent light source scales as 1/(distance to the light)^2. For this law to be different in another location in the universe would mean that the area of a sphere there would not be equal to 4 x (pi) x r^2 which means that space in that region wasn't three-dimensional, a result which is unphysical.

Finally we look at constituitive laws which describe the workings of physical processes. A good example would be special relativity. If we imagine a location in space in which special relativity does not hold, then in that region of space it would be possible for effects to be observed before their causes have happened i.e., that region would exhibit acausality where things like energy conservation, time measurement, and even arithmetic would be meaningless.

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  • If dimensionless constants (like the ratio of the mass of an up quark to the mass of an electron) could vary from one part of the universe to another, would you count that as a variation in the laws of physics? Constants do appear in the equations, but your three cases of laws don't seem to cover this type of variation.
    – Hypnosifl
    Apr 11 at 21:17
  • I would disagree with your conclusion. It largely depends on the type of universe we are talking. After all, even this universe supposedly started with Big Bang, huge imbalance in matter and energy, seemingly coming from nowhere.
    – rs.29
    Apr 11 at 21:37
  • @rs.29, try posting this question on the physics stack exchange and see what you get. Apr 11 at 22:34
  • @nielsnielsen Physics SE is mostly concerned what is (in our universe) , not with possible hypothetical universes.
    – rs.29
    Apr 11 at 22:36
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    Does he say that there's no way to blend them into a larger multiverse? My understanding is that there are theories like eternal inflation where the values of these constants are set dynamically shortly after the Big Bang by a process called "spontaneous symmetry breaking", this page says the result would be different "bubble universes" separated by "domain walls" inside which space would be inflating too rapidly for any causal influences to cross from one to another.
    – Hypnosifl
    Apr 11 at 23:02
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Newton was able to unify heavenly motion, with Earthly physics - it used to be thought they were just different places. Currently, the inside of a black hole does not obey our physics, because our theories don't work there - we don't have a quantum-gravity theory to account for small scales with high gravity.

You have it backwards. We don't have a theory, and just know it works everywhere. We look in different places, and then we make theories to make sense of them, and hopefully gain bonus information on how to make sense of other phenomena too, or how to look in new places, or how to build better tools.

The speed of light varying, is a set of speculative hypothesees suggesting the speed of light may have changed over time or in other ways - is being looked into. There are speculative observations of the fine structure constant varying across the visible universe

It is thought that all the forces were one force in the early universe, & it decayed into the current set through spontaneous symmetry breaking

Our universe has we currently think 19 independent fundamental constants. So it is logical to wonder what would happen if these varied - that can be linked to the anthropic principle, and the idea of cosmos/es iterating these parameters, but the current set being required for there to be any minds in a universe, to ask these questions.

Heuristic arguments have been made that a 'surface' or constrained space of lower dimensions, is necessary to find a 'sweet spot' of spatial interactions, that in higher dimensions than our 4/5D it magnifies the equivalent of our 'three body problem', with no stable orbits. We have structural reasons to do with the mathematics of octonions to think there are ten space dimensions + time in reality as whole- I like this discussion of what ten spatial dimensions might be doing.

Noether's theorem shows the laws of physics being the same in different spatial locations and at different times, are directly equivalent to the laws of conservation of momentum and energy respectively. And, they seem to hold pretty well. We know the acceleration of the expansion of the universe violates energy conservation. The big bang is a challenge, there are ideas the net energy & momentum were zero, but it's so far proving difficult to see how that could be made to work.

So, yes the laws we experience are contingent, and may be local. But they mesh together, producing many complex consequences from a set of constants, and initial conditions. So it's not like 'anything goes'.

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Poincare used to describe the consistency of Non-Euclidean geometry in details assuming a universal physical law different than ours such that one's body shrinks as one walks into its edge due to its unique temperature distribution law of inverse square of radius (forgot the source though)... So at least Poincare had no trouble to assume there're contingent different physical laws possible in other universes.

Also Leibniz claimed physical laws hold universally of all substances in this, but not in all possible universes as here:

a. Absolutely universal truths: those truths definitive of this universe as being the most perfect universe. Leibniz writes: “Indeed, I think that in this series of things there are certain propositions which are true with absolute universality, and which cannot be violated even by a miracle”.

b. Universal-physical truths: the laws of physics and other such efficient causes, for example; truths which hold universally of all substances in this, but not in all possible, universes, but which also could, in principle, be violated by a miracle, in accordance with overall divine providence

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Science deals with empiric truths (truths that hold for our human experience), not final truths (universal truths, which are moreover the target of philosophy).

In consequence, laws of physics are dependent on our experience, which is directly dependent on our human perception.

If perception would be different, then, different rules --perhaps rules that would break the physical rules we know-- would exist and be logically valid.

Following, an example.

Laws of thermodynamics are intrinsically based on our sense of time. And according to many branches of philosophy, time is a subjective byproduct which is produced by reason, and serves as a context for ordering experience (see Kant's Critique of Pure Reason).

So, according to our experience, heat tends to propagation, and that's a direct consequence of the way we process perception.

If our sense of time would be different, the order of events would be different, even the opposite. Negating such possibility is stating that time is universal, precisely the opposite to what Kant et.al. suggest.

Therefore, there's the real possibility that perception and reason would work in a different manner, and that we would be able to perceive time in the opposite sense. That would directly negate the second law of thermodynamics. In fact, the law will hold opposite in such context, within all the mathematical and physical rules still holding valid.

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