The Natural Limit to Science

Philosophy Forums Science, Technology, and Math
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I have always seen the Relativity theory as an expression of the natural limit to Man’s ability to utilize the scientific process for attempting to understand the universe. But such a thought doesn’t seem so apparent to many others, so another question that I think Science cannot ever actually answer even though it is answerable beyond the natural limits of Science (physics in this case);

Why does light in a vacuum travel at the particular speed that it travels, c, and not perhaps twice or half that speed instead?

Please don’t be confused by the question. I am not asking why light speed is consistent or why it varies when it varies nor anything related to the alteration of reference frames. But rather I am asking why light travels at the proposed 186,000 miles per second instead of perhaps 1,000,000 miles per second or 10,000 miles per second.

Of course, in physics, we can merely isolate the variables and proclaim that c is that particular value because the other variables are at their particular values and would then be expressing the meaning of relativity, but that is a bit tautological. It would be like saying that 2+2=4 because 4-2=2. The other values could be adjusted to compensate and form the similar question of why a second is as long as it is or why a meter is a long as it is and so on. The real question would go unanswered if it were always merely relegated to each of the other variables being what they were. But the world of physics and Science has no choice in that matter.

Can any of you logically reach beyond the natural limits of Science so as to answer such a question?

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Do you also wonder why Planck’s Constant is 6.626068 × 10-34 m^2 kg/s?

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The question is readily answerable.

Light in vacuo moves at the speed that it does. It doesn’t move at twice this speed, or half this speed. In natural units, we say this speed is 1, and say c=1. That’s just another way of saying light moves at the speed that it does. As for why its speed is 186,000 miles per second, that’s just choice of units. Another choice of units is metres per second, and these units are defined using the motion of light. See en.wikipedia.org/wiki/Second for the definition of the second:

“Since 1967, the second has been defined to be the duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the ground state of the caesium 133 atom.”

The NIST fountain clock employs lasers and a microwave cavity to cause hyperfine transitions, which are electron spin-flips within caesium atoms. The electron is electromagnetic, it’s literally made from light in pair production, and the spin-flip is an electromagnetic phenomenum. It emits microwaves, light in the wider sense, of a given “frequency”. These microwaves are then received by a detector:

But note that frequency is measured in Hertz, which is defined as cycles per second, and we haven’t defined a second yet. Instead, we’re defining the second. What the detector actually does, is count incoming microwave peaks. When it gets to 9,192,631,770, then that’s a second. Hence the frequency is 9,192,631,770 Hertz by definition. Then we define the metre, and this too is defined via the motion of light:

“The metre is defined as the distance travelled by light in free space in 1⁄299,792,458th of a second.”

Then we use our second and our metre to measure the speed of light in vacuo. And we measure it to be 299,792,458 m/s. We always do, because our units are derived from the motion of light. It doesn’t matter how fast the light is moving, you count 9,192,631,770 incoming microwave peaks, and that’s a second. Then you watch light moving for a fraction of this second to mark out a metre. Then you use these units derived from the motion of light, to measure the motion of light.

Press a magic button that makes all electromagnetic phenomena proceed at half their former speed, be it the electromagnetic hyperfine transition or the propagation of electromagnetic waves, and you still measure 299,792,458 m/s. Because when the light goes slower the second is bigger, and the slower light and the bigger second cancel each other out. You don’t notice it locally, because you’re made of electrons. And other things too, but the same principle apples. Electrons are electromagnetic, and they are made of light. So are rods and clocks…

And so are you.

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Naahhh… I can’t let you get away with that one. We acknowledge that all “things” are made of that same EM wave stuff, light. Thus the size and shapes of all things are directly related to those EM properties. If the EM were to magically double its speed, the entire universe and everything within would immediately double its size and just as you point out, our measurements would not change. Perhaps it is increasing and decreasing randomly. We would never be able to tell as long as it was uniform.

But you have merely said that light travels at 186,000 miles per second because 1 second is how long it takes light to travel 186,000 miles. That was the tautological “2+2=4 because 4-2=2” response that I warned against.

Perhaps if I reword the question (always having to do that these days);

Given a large void in space that is magically absent of any perceivable motion other than a single photon traveling from one side of that void to the opposite. The void is large enough that it takes a while for it to get to the other side. Now the question;

Why did it take that particular length of time instead of propagating faster or slower? Or why did it take any time at all?

The traditional Science/physics answer is merely, “because that is how long we observed it to take.” And that is fine for Science, but this is a PHILOSOPHY forum.

A) What is the REASONING for why light takes time to travel at all?
B) What is the REASONING as to why it travels at that particular velocity?

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Ignore him.

My response is still the same:

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But that isn’t an answer.

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Yes, it really is. The speed of light is just a physical constant of the universe. To question that is to question every other physical constant is to question why we exist the way we do in the first place. People get all enamored with the speed of light…and it is cool and very strange, don’t get me wrong, but the question is on par with “Why are we here?”

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Because it is the final cause of waves and particles to move. In being both a wave and a particle as well as neither a wave nor a particle, light manifests the ultimate realization of this final cause and (in a vacuum) it travels at the speed which other things may approach but never truly reach.

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Well, that would be true if I had asked for what purpose it travels at any speed. I am asking of the cause for it to have any particular speed even though all other known interferences have been removed.

If there is nothing to slow it down, why isn’t it moving faster?

I guess that I don’t understand what is meant by “final cause”.

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You wanted to get philosophical, I figured I’d just go with the source material.

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People seem to be hung up on purpose when I am referring to physical or logical causation.

Final cause or telos is the purpose or end that something is supposed to serve.

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I don’t think we understand light well enough to adequately describe either of those elements. And absent sufficient knowledge, there can’t really be a good answer to those questions, good though they may be.

Michio Kaku still does a lot of touring, see if you can go to one of his events (they are usually reasonably small) and ask him that question. Clarify that you mean what you mean and not what people take you to mean – both modern language and modern thinking have a hard time separating the various causes as various movements have collapsed many of them into the same thing or entirely excluded others.

It is a good question you ask, but one that I am unqualified to answer. A philosophically minded theoretical physicists could jive on what you are saying – and based on anecdotal experience, I’d say that represents a majority of theoretical physicists (otherwise they’d be experimental physicists) and amongst them I’d wager that those that specialize in phenomena like light (it isn’t optics – I don’t know what it is called though, probably part of quantum? No idea) would have an answer for you. I’d be all calculus and weird shit, but hey, that is theoretical physics.

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Oh dear. I think you might be under rating yourself and certainly over rating others. Even ancient Greeks could address this question and to a degree, did.

This is actually a question of logic as it pertains to metaphysics. Physicists are programmed into mathematics by the necessity of their work. But mathematics is a measurement or a comparison tool. Mathematics and physicists can only tell you how big one thing is relative to something else. That problem is the very instigation of this question. Physicists, especially theoretical or speculative physicist have more trouble than many others. When a physicist steps out of his confined processes into the realm of metaphysics or “what is existence anyway?”, he becomes like a small arrogant child presuming all kinds of fantasies and being promoted by social engineering so as to be regarded as the high priests of intelligence. But they are but technicians to the logicians of metaphysics. Science merely verifies what is speculated.

It is entirely a matter of logic. No Science required at all.

Think about why anything would take time to have affect on anything else. It is entirely an issue of logic. No observations or Science necessary.

Object A is going to affect object B which is going to affect object C. It doesn’t matter what the affect is exactly. Why isn’t C affected immediately? And since it isn’t, why does it take longer to affect C than it did B? And finally, why did it take the particular amount of time that it took - and logically must always be so regardless of anything Science ever attempts to observe.

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Ho boy.

The speed of light is the speed of light. Light can’t move faster than the speed of light because it is the speed limit of the universe. Why it is the speed limit is again a question of physical constants. It just is.

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I suspect there has never been a greater impediment to Man than that sentiment.

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It’s how it is, James. All the science I gave you was correct. If the speed of light changes, you can’t tell locally. But when you compare notes with somebody else where the speed of light is different, you can tell there’s a difference. But people call it time dilation.

That’s exactly how it is. We use the motion of light to define the units which we then use to say how fast the motion of light occurs. This really is why we always measure the local speed of light to be the same.

There is no such thing as a length of time. Clocks don’t clock up time. What they clock up, is motion. Assume you can observe this photon, and you use a clock to measure the time it takes to traverse the void. If it’s a mechanical clock, it employs the rotatory motion of cogs and sprockets. If it’s a quartz clock it employs the oscillatory motion of a crystal. If it’s a light clock, like one that employs a photon bouncing back and forth between parallel mirrors, it employs the motion of light. You express the time for photon1 to cross the void in terms of the number of times photon2 bounced between the mirrors.

Because time is a cumulative measure of motion.

It’s all down to the nature of space, which can be likened to an intangible elastic solid, where permittivity and permeability are akin to the shear modulus of elasticity and density. And that velocity changes, but we don’t recognise it as such, and call it gravitational time dilation instead. At the risk of repeating myself: a gravitational field is a region of inhomogeneous space, wherein low gravitational potential represents high stress-energy density. It’s effectively a pressure gradient wherein the speed of light c = √(1/ε0μ0) varies because vacuum impedance Z0 = √(μ0/ε0) varies. In essence the “strength of space” varies. The result is gravitational time dilation and attraction through refraction like a car veering when it encounters mud at the side of the road. This curvilinear motion through space is the result of a gradient in space, and is described as curved spacetime.

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I don’t agree. I think that why “c” holds the particular value that it does in a vacuum is going to be a property of space-time. Understanding the architecture of space-time is going to be important in “c” holds the value that it does. You can use logic to demonstrate that “c” ought be neither zero nor infinity, but beyond that it gets a little dicy. Given some of the discoveries of experimental physics, theoretical physicists can play around with math (logic) to arrive at new answers.

While I don’t really know, my hunch would be that the answer you are looking for can be found by playing around with Maxwell’s equations. Look at special relativity, for example. E=mc^2, so dE=c^2 (because c^2 is just a regular number, like 5, just written in a strange manner. I originally wrote 2c, but that is wrong. Been a while since I had to do any calc, even easy calc). So, the change in energy is equal to the speed of light squared.

Like I said, I’m no physicist and I’m bad with calc, but I’d probably use that relationship and maybe plug it into this:

and solve the resulting differential equation (something well beyond my abilities to do). I’m not sure what you’d want to solve it with respect to, though. Maybe E, so you can use the c^2 thingy later? You’d probably also want to play around with 3+1 spacetime and build that into it. Under other conditions, the speed of light is almost certainly different from c, so the thing would get really weird.

It is almost certainly going to be a function of the curvature of space-time. I just don’t know how to show that. But that is a failing on my part, not on the part of physics.

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None of what you are saying is in dispute. That is why I kept saying it for you. My point is that what you are saying is irrelevant and tautological (pointless). You are not answering the question with any more than “because it is”.

You cannot use physics to answer the question. If you try, you are merely being tauty and saying that “we know that it is because our measurements show it to be true”. I am not arguing whether it is true. I am asking for an explanation as to WHY it is what it is and demonstrating, with your kind help, that Science/physics cannot actually answer the question (and remain Science anyway) and isn’t really supposed to try.

It requires logical METAphysics to get to the answer. Physics is merely about the relations between measurements, nothing more. But I am not asking for the relation between any measurements. I am asking for an explanation for the cause of a constant in our universe.

What would cause ANYTHING to be constant in the universe (as anthem pointed out)?

You have to think outside the box of Science and into the logical (and math) realms of any and all reality (all “possible worlds”), observations of what happens to be before you at the time, are not required.

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Perhaps a clue;

Philosophically what causes change of anything?

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Philosophically, everything is in a constant state of change. The question oughtn’t be “what, philosophically, causes change?” but rather, “what, philosophically, causes us to conceive not-change?”. You can cite Heraclitus, the Yijing, or whatever other foundational philosophical text on that one.