I Why is there a universal speed limit, c, and why is it what it is?

Click For Summary
The discussion centers on the concept of a universal speed limit, denoted as "c," which is the speed of light. Participants explore the reasons behind this limit, questioning whether it arises from physical measurements or logical constructs. The conversation delves into the implications of a four-dimensional spacetime framework, suggesting that the speed limit is a natural consequence of how physics manifests for observers within this structure. Additionally, the dialogue touches on the philosophical aspects of causality and the foundational postulates of relativity, emphasizing that the existence of a universal speed is tied to the properties of spacetime itself. Ultimately, the nature of "c" remains a complex topic that intertwines physics with deeper philosophical inquiries.
  • #61
Dmitry67 said:
P.S.
String theory does not change anything, it just adds 1 more level.

One more level of cards to an already rickety house of cards yes.

Whilst I find it an interesting diversion I don't think it ever has much of a chance as a ToE.
 
Physics news on Phys.org
  • #62
No matter what you believe in, there should be some kind of extra level (TOE, LoopGravity, EternalInflation, whatever) because otherwise it would be difficult to explain the values of the parameters of the standard model without assuming them adhoc.
 
  • #63
Dmitry67 said:
No matter what you believe in, there should be some kind of extra level (TOE, LoopGravity, EternalInflation, whatever) because otherwise it would be difficult to explain the values of the parameters of the standard model without assuming them adhoc.

Well of course there should be a better theory.

If maths doesn't solve the problem it doesn't mean you need extra bells and whistles necessarily in the form of 11/22 dimensions etc, it might mean there is a problem with your maths.

An awful lot of people happen to believe that 3+1 dimensions are all that are required, that and a quantum theory needs to stop being incomplete. So I'd disagree these extra levels are necessarily likely to be more valid, not every one is messing about with 9827362 dimensions E11, or some twisting or spinors or whatever space to solve these problems.

It could just be that GR is wrong or as is more likely QM is. If you think that isn't the case then by all means explore other areas. I just think they are likely to be endlessly unfounded. I'd of course be delighted if you (by which I mean anyone) proved me wrong. :smile:
 
  • #64
Endlessly?
I strongly believe that we are very close to TOE.
Having an infinite number of turtles all the way down will be quite dissapointing.
 
  • #65
Dmitry67 said:
Endlessly?
I strongly believe that we are very close to TOE.
Having an infinite number of turtles all the way down will be quite dissapointing.

Well that's a matter of opinion I don't think strings has any likelihood of turning up evidence in the foreseeable future tbh. Where incidentally do you think this ToE will come from: the standard model or Strings or other?

I think if we find Higgs it will certainly make the standard model easier to support. It might be something about gravitational concerns causes the problems with QM. If not then strings wins whatever happens as usual and LQG still won't be all that inconvenienced because ultimately it should explain everything strings does without the strings.
 
  • #66
bobc2 said:
DaleSpam, what is your assessment of the "Theory of Everything"--assuming Stephen Hawking is proven correct in his pronouncements?
I don't know Stephen Hawking's statements re a TOE, but my statements above would apply to a TOE also. All science could tell us is that it accurately predicts the results of experiments, not why it does.
 
  • #67
Dmitry67 said:
Why 1+1=2?
Can you answer the question?.

Because of the definitions of one, two, plus, and equals. Because we define two to be the sum of one and one.

It is like saying why does t h e spell "the". Because of what the word "spell" means.
 
  • #68


nitsuj said:
You set the context to "Science is fundamentally incapable of addressing "why" questions". Well sticking to that, it is also incapable of "answering" questions of anyform.
No, science most definitely can answer questions of the form: "Does the mathematical model X correctly predict the observation Y in experiment Z to within experimental error?"
 
  • #69
pip1974 said:
There's more to science than the scientific method!
Such as what? There are ancillary things such as the scientific community, the scientific literature, and the philosophy of science. But the core of science is the scientific method. Other pursuits (e.g. law) have a community, literature, and philosophy. What distinguishes science from other such pursuits is the scientific method. That is the center of science so if a question cannot be addressed experimentally using the scientific method then it is not a scientific question.

pip1974 said:
Why is the sky blue? Can science address that question? Yes!
Why do I come back to Earth when I jump in the air? Can science address that question? Yes! Of course it can.
This is a good example. The only way that science can answer this is by pointing to a mathematical model which accurately predicts the observation. Science cannot tell you why that mathematical model works. Remember, your original post in this thread was specifically looking for some explanation beyond the mathematical model:
pip1974 said:
we can explain and describe almost everything we can observe. But what's missing is the 'why' bit.
And this "why bit", why the model works, is what science cannot provide.
 
  • #70
DaleSpam said:
"Why?" is the most important question! And in science leads to the next level of understanding and more questions, that normally begin with "Why...".

DaleSpam said:
This is a very common misunderstanding. Science is fundamentally incapable of addressing "why" questions. Science can only answer questions of the following form: "Does the mathematical model X correctly predict the observation Y in experiment Z to within experimental error?". Even if the answer is "yes" the scientific method does not and cannot answer the question "why" the model works.

I disagree that it is a common misunderstanding. What I do think is a frequent recurring problem in these forums is DaleSpams point of view.

What many if not most of the people asking questions here want to know is why. And it seems the group of people replying are satisfied not to know, don't care why, and discourage people from asking why.

Regarding "Does the mathematical model X correctly predict the observation Y in experiment Z to within experimental error?"", if there is a ball, with a mechanism inside, that moves in different ways under different conditions, and by observing the ball one can create equations that predict how the ball will move, that is insufficient and not what people asking questions want to know. They want to know about the mechanism inside. And if you can come up with a design of the mechanism that works, then it will also be accurately predicting observations.

The problem is too many people are satisfied with only going as far as has already been gone. As long as they can predict what the ball will do, they are satisfied without knowing what is inside. Other people want to not only know what we know so far, but go farther and deeper. It is said that there are things we have understood for a hundred years such as relativity. The more I am reading, the more it seems that is not the case. Either the questions are not being answered well, or we really do not understand relativity yet, and it should not be claimed that we do, and questioning further or even questioning what is claimed to be well established should not be discouraged.
 
Last edited:
  • #71
CosmicVoyager said:
I disagree that it is a common misunderstanding.
Then prove me wrong by showing me how you can use the scientific method to answer questions of some other form.
 
  • #72
DaleSpam said:
Then prove me wrong by showing me how you can use the scientific method to answer questions of some other form.

I think the problem may be that the people I am referring to are claiming that questions are not scientific when they are. That is, that the answer could be a "mathematical model X correctly predicting the observation Y in experiment Z to within experimental error", but that current equations already do that. In other words, there is a mechanism inside the ball, which we could develop a mathematical model for that would predict observations, but because a model already exists that predicts without a complete description of all structure, they have no interest in doing so. That is sufficient for practical applications, but people want to fully understand the structure of the universe.

Advice to people asking question: Many contributors here have an allergic reaction to the word "why". Instead say something such as "How is it that...". I have discovered that by actually simply avoiding using the word "why" while still asking essentially the same question, you get better responses, and avoid the negative reponses to "why" that we are so annoyed with.
 
Last edited:
  • #73
CosmicVoyager said:
I think the problem may be that the people I am referring to are claiming that questions are not scientific when they are. That is, that the answer could be a "mathematical model X correctly predicting the observation Y in experiment Z to within experimental error", but that current equations already do that.
That is fine. If you or pip1974 can re-phrase the question into that form then I would heartily agree that the question is scientific.

CosmicVoyager said:
In other words, there is a mechanism inside the ball, which we could develop a mathematical model for that would predict observations, but because a model already exists that predicts without a complete description of all structure, they have no interest in doing so. That is sufficient for practical applications, but people want to fully understand the structure of the universe.
What you are suggesting here is that people use a more complicated mathematical model than is necessary to explain the data. I do not, in principle, have any problem with that. It does violate Occham's razor, but it is not contrary to the scientific method.

CosmicVoyager said:
Advice to people asking question: May contributors here have an allergic reaction to the word "why". Instead say something such as "How is it that...". I have discovered that by actually simply avoiding using the word "why" while still asking essentially the same question, you get better responses, and avoid the negative reponses to "why" that we are so annoyed with.
Excellent advice.
 
  • #74
DaleSpam said:
TWhat you are suggesting here is that people use a more complicated mathematical model than is necessary to explain the data. I do not, in principle, have any problem with that. It does violate Occham's razor, but it is not contrary to the scientific method.

I anticipated bringing up Occam's razor, and almost included that. LOL I don't think it is the simplest answer because questions still remain. Why is it moving that way? What is inside the ball? And I don't think there will be an infinite regression of why questions. I think a point can be reached where it finally all makes sense. Where the picture is complete. Where apparent contradictions are resolved rather than just being adjusted for.David Bowman in 2010: "You see, it's all very clear to me now. The whole thing. It's wonderful."
 
  • #75
CosmicVoyager said:
And I don't think there will be an infinite regression of why questions.
You obviously don't have any four-year-old kids.
 
  • #76
CosmicVoyager "Advice to people asking question: May contributors here have an allergic reaction to the word "why". Instead say something such as "How is it that...". I have discovered that by actually simply avoiding using the word "why" while still asking essentially the same question, you get better responses, and avoid the negative reponses to "why" that we are so annoyed with."

I couldn't agree with you more Cosmic. It seems the issue is the one answering cannot (i hope this is a word) contextualize a response.

Questions like "What makes the sun hot"
seems to be a world apart from "Why is the sun hot", for some people. (Note:dalespam I don't literaly mean one world distance between the two questions, that's merely a figure of speech, such as the question why)

Kids, perfect example. With no use of the scientifc method, your kids will grow up to develope an "understanding" of things of allsorts (and probably,thanks to you, better then most). I am sure observing your kids you see their understanding of the world around them "evolves". There are prerequisites in this evolution. When the question "where do babies come from" comes up, I am sure you will provide an edited explination. One that your kid is satisfied with and is congruent with their understanding in general.

To sum it up, a question, one human to another (providing context for you) is the same as asking "help me understand xyz so that it fits with my current understanding in general".

It's no wonder that after 18+ years of developing an understading (whether conscious or not) of time, that when one crosses paths with the idea of relativity many more questions come up, as we rework our "general understanding" so that everything fits together in a way we are comfortable with.

Perhaps, dalespam, that is why you have no issue with there being a universal speed limit, because you have seen so many equations and graphs that you have "seen" how there is a universal speed limit. You have a "feel" for this speed limit. It fits into your "general understanding", quite simply you accept it.

Your "why" question has been answered.
 
Last edited:
  • #77
nitsuj said:
It seems the issue is the one answering cannot (i hope this is a word) contextualize a response.
I believe that my responses have "properly contextualized" the question that I responded to:
pip1974 said:
we can explain and describe almost everything we can observe. But what's missing is the 'why' bit.
The above question is not akin to your "what makes the sun hot" vs "why is the sun hot" example. I think that you are the one having trouble "properly contextualizing" the question. He is specifically rejecting answers of the form that science can provide. If you disagree then kindly re-phrase the question in the form I have mentioned above, because I am obviously too stupid to see the rephrasing which is so clear to you.
 
  • #78
CosmicVoyager said:
I anticipated bringing up Occam's razor, and almost included that. LOL I don't think it is the simplest answer because questions still remain. Why is it moving that way? What is inside the ball? And I don't think there will be an infinite regression of why questions. I think a point can be reached where it finally all makes sense. Where the picture is complete. Where apparent contradictions are resolved rather than just being adjusted for.

I think it's legitimate to hope for something like that. The problem is, what do you do if there are competing theories which all "explain" a currently "incomplete" theory, but there is no way to distinguish between them experimentally, even in principle? We actually have that situation in quantum mechanics right now, with its various interpretations.
 
  • #79
Meanwhile, I will attempt to give an example of scientific "WHY"

Q: Why CKM mixing angles are not = 0?
A: Because if they were equal 0, there won't be any difference between matter and antimatter. After the annnihilation, there would be just light, no matter, and no conscious observers.
 
  • #80
DaleSpam "The above question is not akin to your "what makes the sun hot" vs "why is the sun hot" example. I think that you are the one having trouble "properly contextualizing" the question. He is specifically rejecting answers of the form that science can provide. If you disagree then kindly re-phrase the question in the form I have mentioned above, because I am obviously too stupid to see the rephrasing which is so clear to you."

I don't know what the question was but if "He is specifically rejecting answers of the form that science can provide" that should help you "contextualize" your response, no?

Don't ever pose me with "If you disagree then kindly re-phrase the question in the form I have mentioned above, because I am obviously too stupid to see the rephrasing which is so clear to you" it's insulting to both of us. You couldn't convience me, despite you trying, that you are "stupid". In fact I think the issue is somewhat the opposite, you need to stop being so "smart".
 
Last edited:
  • #81
Dmitry67 and DaleSpam. Scientific method is a tool, a method in fact, that allows us to answer questions about the natural world.
If someone asked me why the sky is blue, I would be able to understand their question and give them an answer based on my knowledge of science. It's a shame you claim you wouldn't be able to do the same thing.
I wonder what certain people's motives are for trying to answer questions here. Seems to be a rather egotistical activity to me, in which the prime motive is to demonstrate knowledge rather than share it.
Here's a challenge. Suppose someone were to ask "why can't a spaceship go faster than the speed of light", I bet I could give a really good answere that would satisfy most inquisitive people, and I would be able to pitch it at the appropriate level without trying to show off how clever I am. I bet you couldn't.
 
  • #82
As usual in these arguments its about semantics and isn't really important. Some people are restricting the language to a more pure form of science and some are not, it's all basically correct though, it just depends on how you phrase it. We all know the difference between why does the Universe exist at all, philosophy, and why is the sky blue. It would be couched in a proof in science, such as: I can show how scattering in an a atmosphere favours some wavelengths, with x experiment, that would show y results, or, we could say the reason why it is blue is because of the above because we already accept as an axiom that the reasoning is solid and is self evident.

The fact remains science at the research level does not deal in whys so much as hows. It only deals in whys when the facts are taken for granted. One is pure science the other is science explanation. Why do men walk on two legs is a valid question only if it is appropriately asked and answered. How did men come to walk on two legs would be the basis of research, why wouldn't unless it was a weaker more philosophical form of science, like anthropology and even then it would probably not be couched in too many whys if it was a research paper.
 
Last edited:
  • #83
Calrid It's not simply semantics, and it is really important that people don't piss on other people's pursuit of "why" something is simply because an f-ing graph doesn't translate to their accepting it as the answer "why".

If someone has their head so far into the scientific method that they cannot translate it back to the "real" world, then the purpose of the scientific method in the "real" world is lost.
 
Last edited:
  • #84
nitsuj said:
Calrid It's not simply semantics, and it is really important that people don't piss on other people's pursuit of "why" something is simply because an f-ing graph doesn't translate to their accepting it as the answer "why".

Oookay, we'll have to agree to differ. I think it is semantics you don't.

Semantics is a vast part of philosophical debate that has impact on all areas of reason, it is highly important. I did not mean to demean it but I think that overall it is unimportant in this context because of the way ideas are formulated, or theories, the more solid science. Just meant to say that it is a matter of connotation, how you use language and in which way becomes deeply significant in logic and reason. Ultimately though just be careful you are not just saying the same thing with different words. We can dispense with whys in science at certain levels: the cutting edge for example.

Why is more often a philosophical question, how is more often in the remit of science. That's not to say they don't have a utility in both, I just question if there is all that much of a difference in how and why in certain ways of saying things and in certain fields.
 
Last edited:
  • #85
I'm convinced.

I admit poor understanding of the meaning (and in turn importance) of semantics.

"I did not mean to demean..." clarifies it for me, and I retract my claws :)

Calrid, your second post almost has me understanding dalespam's point of view. A seemingly impossible task just a few posts ago.
 
Last edited:
  • #86
nitsuj said:
I don't know what the question was but if "He is specifically rejecting answers of the form that science can provide" that should help you "contextualize" your response, no?
I quoted it directly in post 77, to which you were responding. I re-post it here again for your convenience.
pip1974 said:
we can explain and describe almost everything we can observe. But what's missing is the 'why' bit.
Note, that you can click on the little arrow to be taken back to the post and see it in context.

I don't think that I am in any way distorting pip1974's intention with that sentence, nor being artificially obtuse, nor "improperly contextualizing". He apparently knows and understands the mathematical model and its predictions. What he specifically wants in that quote is the reason why the model works, and that is something that science cannot ever answer.
 
Last edited:
  • #87
pip1974 said:
If someone asked me why the sky is blue, I would be able to understand their question and give them an answer based on my knowledge of science.
That is a good example. What would your answer be to the question "Why is the sky blue?" And I will remind you of your own comment which sparked this debate:
pip1974 said:
we can explain and describe almost everything we can observe. But what's missing is the 'why' bit.
So by your own criteria that we are discussing, an explanation and a description (i.e. a mathematical model) is not sufficient to answer "why".
 
Last edited:
  • #88
DaleSpam said:
This is a very common misunderstanding. Science is fundamentally incapable of addressing "why" questions. Science can only answer questions of the following form: "Does the mathematical model X correctly predict the observation Y in experiment Z to within experimental error?". Even if the answer is "yes" the scientific method does not and cannot answer the question "why" the model works.

That's much too pessimistic IMHO! :rolleyes:
No explanation is never certain of course, and in general no explanation is perfect, but science does help to increase understanding. For example, if you were right, Newton's work on mechanics was a failure*. However, most people would agree that he did giver deeper insight in the "why" of such things as Kepler's orbits: instead of just a magical formula, it started to make sense.

As a matter of fact I would have abandoned science a long time ago if it did not deliver on this point. :smile:

* But how we are to collect the true motions from their causes, effects, and apparent differences; and, vice versa, how from the motions, either true or apparent, we may come to the knowledge of their causes and effects, shall be explained more at large in the following tract. For to this end it was that I composed it.
 
  • #89
That last bit you quoted was specifically in reference to the original question. You don't need to remind me. I would explain that the sky appears to be blue because of refraction. I could point the questioner to the relevant sources if they need more detail.
If asked the original posters question, I'd say "I don't know, I really don't think anyone knows why that is the case but someday if a unifying theory is found a clearer picture may emerge". That's what I'd say. I wouldn't start having a go at the questioner for not putting questions in the right form, and would not persist in a pointless semantic debate with someone who just said they understood the question. That's it from me.
 
  • #90
CosmicVoyager said:
[..] They want to know about the mechanism inside. And if you can come up with a design of the mechanism that works, then it will also be accurately predicting observations. [..]

Obviously. Now people come up with different possible answers - "the" design that works is an illusion, usually several could work, with the existing knowledge. I would still agree that that is more satisfying than "we don't know" or "that question can't be answered", which probably is a facade for "we are clueless".

And we gave you several possible answers (models) in this thread; you can freely choose the one you like or the one you think is more plausible or the one that for you looks the simplest. :-p
 

Similar threads

  • · Replies 47 ·
2
Replies
47
Views
5K
  • · Replies 9 ·
Replies
9
Views
1K
  • · Replies 25 ·
Replies
25
Views
2K
Replies
41
Views
5K
  • · Replies 47 ·
2
Replies
47
Views
2K
  • · Replies 45 ·
2
Replies
45
Views
6K
  • · Replies 19 ·
Replies
19
Views
2K
  • · Replies 12 ·
Replies
12
Views
3K
  • · Replies 10 ·
Replies
10
Views
1K
  • · Replies 5 ·
Replies
5
Views
1K