I am inspired today, once again, by the idea of duality and its fundemental role in our physical reality, from electrical duals, to quantum duals, to the round trip of light (earlier post) and so on...

The more time goes by and the more I think of the world as an expression of Duals (the formal term) the more I realize that duality itself may be the unifying property of the universe that all things emerge from.

I cant help but think that duality is a profound insight of the universe, but I havent quite connected the dots yet... All I know is everything we talk about seems to be only valid in duals and becomes unknowable when we try to seperate those duals in some way...

I am going to call it "The Iron Curtain of Duality"... but I feel like I need to invest time thinking about this, something is there.

Maybe because the only way we (part of the universe) can understand anything is by breaking it into smaller parts and study the relations between them? It's always the relation that we call "law". And relations need at least two parts. Maybe?

@3ammo the problem with that logic is that we already can experementally prove that relativity is correct so any conventional measurement is moot going in.

Moreover the idea that speed of light is a constant is not what is the issue. The speed of light **is** a constant when measured round-trip, that is experimentally provable. What is not a postulate and the part we cant prove is that the speed of light is a constant one-way regardless of orientation. We take that to be the case in relativity as a matter of **convention** not as a postulate. The reason we do so is because even if it is not symmetric it wont change any of the results, therefore any arbitrary convention works, so we pick the easiest one.

Regardless you still cant actually measure it one way, if you do so conventionally you wont account for time dilation at all and get an incorrect answer where using the relativity approach you will get a more accurate answer but it will be interently a two-way measure.

@freemo So how do we "prove" relativity is correct?

We are Newtonian people, then this guys comes along and says the speed of light is constant, so we set up an experiment to measure the speed of light (one trip, round trip, doesn't matter). We are Newtonian people, so we have absolute space and absolute time and absolutely no problem synchronizing distant clocks. And we find that the speed of light, in our Newtonian understanding of what it means to measure it, is constant. But that breaks our Newtonian understanding! We thus find a contradiction between theory and experiment even though the experiment was interpreted within the theory. What now?

The guy then comes and says: I told you so. The speed of light is constant, and here's how you should think about space and time from now on.

Someone says: but the way you set up the understanding of space and time makes it impossible for the speed of light to be *measured* to be any different!

The guys replies: Exactly my point!

People: Hmm...

@3ammo The problem here is if you pretend we are newtonian people (which we are not since the world is relative and not newtonian) any attempt you make to measure the speed of light accurately will give contradicting and failed results, in part because you assume there is no problem synchronizing clocks when in reality there is.

If i just assume a newtonian world, sync up two clocks at rest then transport the receiving clock to a distance location, measure the speed of light, then bring the clock back and compare I will get one measure for speed of light. If i do the same experiment but this time the transmitting clock is the one physically moved I get an entierly different measurement for the speed of light. Since we are pretending the world is newtonian it essentially shows us little more than "it is impossible to measure the speed of light (using newtonian physics), you will get different values when irrelevant aspects of the experiment change!".

In short because relativity is more true than newtonian physics it is only using relativity you can measure speed of light at all (albeit it 2-way speed of light), and newtonian physics makes it impossible to accurately measure the speed of light at all.

@freemo My point is not to pretend that the world is Newtonian, I simply meant our state of knowledge, our working theory was Newtonian. I was answering the question of "How do we prove relativity to be correct in the first place?" And that is by finding a contradiction between the Newtonian view and the measurements made within the Newtonian view.

@3ammo sure.. which means the fact that you think you can measure light one way in the newtonian view, and it turns out you cant (without getting contradictory results) only proves the original assertion, that is, that light can only be measured round-trip and it is fundementally impossible to measure one-way speed of light.

@freemo I'm really fine with that, I keep telling you

@3ammo I know, just saying because im not sure it makes what you say relevant to the topic if we both agree what I said to be true.. my two assertions are threfore valid.. 1) you can only measure light 2-way 2) the speed of light being instantaneously constant is a convention and not an assertion as to how it is in real life.

@freemo Yeah I'm writing the other reply. I think we actually agree in a certain sense. You want to call it a "convention" because of your view of reality as you explained it, I want to call it a "postulate" because of the way I see theory and reality. It's a philosophy discussion at this point (this is not meant to be disparaging).

@3ammo I'm not sure if its a philosophy difference so much as a definition one.. though if we agree on most of what I said its hard for me to see how your perspective is different at all. You want to call it a postulate, but if your definition of postulate is the same as mine im not sure how if we agree on everything else.

@freemo Because then everything is a convention, if we do it your way. Which is fine by me, all theories, in the end, *are* conventions.

Any theory and any framework is a set of choices, these are postulate. You say that calling it a "postulate" says something about the true nature of things, or reality, but it doesn't. As long as you have a consistent set of postulates that can describe measurements, you have a working model of reality. But you can also have a different set of postulates that describe the same measurements. In that sense, all postulates are conventions. I prefer to keep the word "convention" for details within a theory, not its building blocks.

@3ammo well no if we do it my way conventions are things we just do to make the math easier but doesnt reflect reality in any way, like "conventional current" in electronics... postulates are assumptions made with or without evidence, about how the world works and used to derrive equations based on that assumption... axioms are assertions of any type assumed to be true... so a postulate and a convention would be the two types of axioms.

@freemo But the general constancy in the speed of light is about more than making the math easier. As we discussed earlier here: qoto.org/@3ammo/10596306468017, the "isotropy" of the speed of light is also directly related to our notions of space symmetry (among other things). This a statement about the world.

On the other hand, I'm not sure how will gravity look like then, since the theory we use relies on spacetime being a 4D-space, that assertion needs Lorentz transformation to be the same everywhere in all directions (constant c). Again, if you wanna call all of that "just making the math easier", I can also agree because I'm fine with the idea, fundamentally, theories are choices of the way to see the world. But I'm assuming that you don't want that.

@3ammo and no, gravity wouldn't change. A lorentz transformation modified so c is asymmetrical would result in the same experimental results as a symmetric c.. the math would be needlessly more complex, but the final testable results would be the same.

If this were true than the asymetry would be testable, which it is not. All your doing is obscuring it in more complex situations and hope something will work out and change the results.. yet it never does if you do the math.

@freemo Like I said, I'm not sure how that works. I have no reply until I actually carry out the construction of spacetime that way.

@3ammo You could just accept it due to the fact that it is accepted by the body of scientists as true who have already done that work. Though I do encourage you to do the exercise for your own knowledge.

@freemo Yeah it's not about acceptance. I wanna do it myself to really see what assumptions will I be forced to make. There's always something to learn playing in the mud.

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@3ammo Agreed, you will certainly learn from that process and it might connect the dots for you as to why an asymetric speed of light would be impossible to test and would in no way change the observed universe

QOTO: Question Others to Teach Ourselves