# Why is there no absolute rest?

It's clear and evident that no particular place in space is special, and nor any particular direction.

It is also true (ignoring relativity) that there is no absolute rest; we cannot determine whether a particle is at rest.

Is this tied to the fact that there is no fixed origin of space? Ie conceiving space as a Cartesian grid then there is a point of origin of the axes; but in actual fact there is no such place.

For supposing that there is such a place, then given a particle in that space we can measure the distance of the particle from it with time; and if this doesn't change we can say the particle is at rest.

Is this a good argument?

(In Aristotelian terms we can say that every Place the particle can occupy is identical).

• Because motion is by its very essence relative. It makes no sense to describe something as in motion without a conception of what it is in motion with respect to. Sometimes, the motion is relative to an implicit background so ubiquitous we may take it for granted to the extent that we are not even aware we are doing so, but nevertheless there it is. Or it may be a conceptual background, such as the one you've painted with your absolute origin. But nevertheless, even in your scenario, the object is in motion, or not, relative to that origin. Commented Apr 24, 2015 at 9:18
• Thought experiment: picture an endless, featureless, gray expanse of utterly empty space. Now picture yourself zipping along at a million miles through it. You wouldn't even be aware you were moving. What's "a mile"? For that matter, what's "an hour"? There is nothing to measure your "progress" against. You wouldn't even be aware of any progress; progress is meaningless. Now, superimpose your imaginary grid on the space such that you can see it. Suddenly, you're moving again! (Note the implicit assumption of constant velocity; acceleration changes everything, but requires energy.) Commented Apr 24, 2015 at 9:23
• @bron: sure - it seems that you're just rephrasing the argument above? So I take we're in agreement. I'd suggest all forms of uniform motions are forms of 'rest'; in the same way that it doesn't matter how I position a box in space - it's still a box. ie taking symmetry into account; and I'd oppose rest to accelerative motion; because in rest nothing fundamental changes - whereas in motion it does; and that's confirmed as you say, that in the first case energy does not change, and in the second it doesn't. Commented Apr 24, 2015 at 10:30
• What I said may or may not be a rephrasal of your argument: what I was trying to underscore is that the notion of relativity is inextricably baked into the concept of motion. The lack of a universal set of coordinates or origin seems a different question to me, except in the sense that absolutism may be a misguided in the broadest sense. Note that my argument would permit the existence of an "absolute box", alone and by itself, because the definition of "box" permits that. Nothing in its conception requires comparison to an external entity. Motion does. Commented Apr 24, 2015 at 10:36
• Well, there is an absolute motion - light? So it's not entirely misguided; it's not my argument as such, I expect it's been already discussed in the literature - but I'm not aware of it; so in effect that's what I am asking for. Commented Apr 24, 2015 at 10:40

If constant change, even when not traversing space, is not rest, then it is a consequence of Heisenberg, and more basically of 'frequency' as an essential aspect of matter due to deBroglie, that there is no absolute rest.

Things either have a frequency, or they cannot be detected. Interference with another thing with a frequency is the only way of detecting things. And to a certain degree, things with no effects do not exist in the same way that detectable things exist. To admit them ontologically opens you up to a profusion of nonsense.

I don't think this is tied to the relativity of space in any important way.

If time is measured as accumulating entropy, then this may have to do with the relativity of the arrow of time. My pet Boltzmann-inspired way of looking at quantum frequency is that what is increasing and decreasing at that frequency is the local component of entropy, and so what is 'waving' is time.

Newton defined relative motion, relative space, and relative time as measurements. You can read that here:

http://plato.stanford.edu/entries/newton-stm/scholium.html

Therefore, anything we measure is by definition relative. You cannot measure absolute rest or motion a priori.

I think it is entirely possible that the speed of light is, in fact, absolute rest. The way I can logically understand entanglement, quantum eraser, and time dilation is only if massless particles at the speed of light are in absolute universal rest.

I think this goes against any current theory and intuition because the speed of light gives the impression of motion. However, if we think the speed of light is absolute rest and classical rest is the opposite, then other "spooky" phenomena becomes less problematic (e.g. that all inertial frames of reference observe the same quantity of C, zero time at the speed of light, instantaneous information with entanglement, and retroactive quantum erasure).