Philosophy Discussion Forums

I suggest that if you want to know more about what dimensional analysis is, you type that term into Google and look at the Wikipedia article on that subject. It will give you the general idea.

We can use dimensional analysis to work out the base units of a quantity and check our equations to ensure that they make sense. For example, as I said:

Classical Kinetic Energy = ¹/₂mv².

So the S.I. unit called the Joule, in base units, can be found from the units on the right-hand side of that equation. They are:

units of mass X units of speed X units of speed.

That is kg X m X s^-1 X m X s^-1 = kg X m² X s^-2.

Now, look at the equation for gravitational potential energy in a uniform gravitational field:

Potential Energy = mgh

Using the same method, the units on the right are:

kg X m X s^-2 X m = kg X m² X s^-2.

Same as the units in the first equation! This is one way of checking whether two equations tell you the value of the same kind of quantity. In this case, energy.

Steve3007 wrote: ↑September 6th, 2018, 4:00 amIf they use "the same maths" and one of them "fails to conform to the rules of mathematics" then so does the other.

Let me give you a simple example of them using the same maths. SR and LET use the same formula for length contraction, but there's a difference in the way they label the data. LET recognises that apparent length contraction is not necessarily actual length contraction because the "contracted" object may not really be contracted (if it's stationary) or that the actual contraction applied to it may be different from the apparent one. SR makes no such qualifications but simply asserts equal correctness to all statements generated from different frames.

If you do assert that there are logical contradictions in GR and SR which don't exist in LET, while at the same time also asserting that they are mathematically identical, these two assertions themselves directly contradict each other.[/i]

They are using the same maths, but they aren't mathematically identical if they're applying different truth values to the numbers that they generate. Arguably then, they aren't using the same maths because the truth values are different, but most people would say that it's the same maths with the inputs and results being treated differently in terms of their meaning.

I pointed out a condradiction between your two assertions.

You're trying to invent a contradiction where there isn't one, and you're doing this on a technical point based on what's included and excluded as part of the maths. It should be obvious to you that such an approach isn't going to get you anywhere other than spending time generating a new wording in which the maths for the rival theories is recognised as being different on the basis of truth labels attached to the data, even though the data is crunched in the same way.

Your answer, in a more recent post, did not address that contradiction. For reference, here is a link to that more recent post:

viewtopic.php?p=319010#p319010

Here is something that you said there:

David Cooper wrote:1=2 is a contradiction. A theory that accepts 1=2 is not the same as a theory that rejects 1=2.

You appear to have ignored my point about your contradiction.

If you want to include that as a difference in the maths, then it's a difference in the maths. It's of no importance to me whether the maths of SR and LET are considered to be the same or different on that basis. The difference is that one tolerates contradictions and the other doesn't.

Rather than pointing out the contradiction again, this time I will ask direct questions and see if you address it in that form:

1. Leaving aside which page they're on, do you acknowledge that the two quotes above are taken from your posts in that physics forum?

I'm quite happy that they're mine, though I haven't looked to check them.

2. If two different theories "use the same maths" (as you put it) and one of them contains logical contradictions, does the other one:

a. Not contain any logical contradictios.
b. Contain logical contradictions.

It isn't about them containing contradictions, but generating contradictions as claims. The difference is in the truth labels attached to the data. E.g. "the rocket's clock ticks more slowly after it accelerates away from the planet" and "the rocket's clock ticks more quickly after it accelerates away from the planet" are given truth labels in SR which give them equal validity, whereas in LET they are given labels which are conditionally true. That can be regarded as a mathematical difference if you want it to be.

David Cooper wrote:You're trying to invent a contradiction where there isn't one, and you're doing this on a technical point based on what's included and excluded as part of the maths.

I suspected that you might see this as a trivial point. I don't think it is a trivial point because I see it as a test of whether you know what the term "logical contradiction" means. Mathematics is the language in which physics is expressed. It is a logically rigorous language. These concepts in physics are then often translated into a language like English. English is not such a logically rigorous language and it is frequently open to ambiguity and misinterpretation. If two theories are mutually logically consistent when expressed in one language (e.g. mathematics) then they must be also be mutually logically consistent when expressed in another language (e.g. English). And likewise if they are mutually logically contradictory in any language. If you've found two theories to be consistent mathematically but you think they're inconsistent when described in English, then you must have got the English wrong. Perhaps because English is prone to ambiguity.

To say otherwise is as mad as saying that two theories can be logically consistent when described in French but not when described in English. The logical consistency, or inconsistency, of a theory does not depend on the language that you speak!

Steve3007 wrote: ↑September 6th, 2018, 5:44 pm

With acceleration and deceleration though, the kinetic energy is being increased or decreased, so if it starts at n, it either becomes n+a or n-a, and n+a = n-a only if a=0.

No, it does not become n+a or n-a. That is incorrect.

I know it's incorrect, but the principle of it being an addition versus a subtraction was the point you were supposed to take from it rather than going into a more long-winded analysis.

I strongly advise you to start you education in physics and maths at GCSE level and work up towards degree level subjects like SR, GR and LET if you want to understood those subjects in sufficient depth to propose replacing any of them.

It was a shortcut to make a point. It's taking long enough writing this stuff without multiplying the work by going for absolute precision on all side issues along the way. I see the errors, and you see them too, but they're irrelevant to the point in question, so don't fixate on such irrelevances.

So if an object is accelerating but its acceleration vector, relative to the Earth, is pointing in the opposite direction to its velocity vector then the magnitude of its velocity, a.k.a. its speed, relative to the Earth, is reducing. Therefore its kinetic energy, relative to the Earth, is reducing. It is accelerating, and its K.E. is reducing. Its speed is reducing. So it is decelerating, and its K.E. is reducing.

It is decelerating if its kinetic energy is reducing, but you're finding a way to use a different meaning of the word "accelerate" to describe the same event. Playing word games isn't helpful. If I use your version of the word though, I can refer to an object accelerating and losing kinetic energy and that object accelerating and gaining kinetic energy, but it is not doing both of those things at the same time, even if calculating events on the basis of different frames creates that illusion. The universe is doing one underlying thing and not both at once.

Do you get all this? It's basic stuff.

Yes - it's basic stuff. It's also a word-play diversion away from the issue which makes no difference to the issue. Your task is to find a point where my argument breaks down; not to nit-pick over irrelevant things where I've taken shortcuts during the discussion of side issues. If you think I can't handle the physics, ask yourself how I wrote the code that handles the simulation on my relativity page. Ask yourself how I wrote the reference-frame camera program that I link to from there. Ask yourself how I write programs like this one: http://www.magicschoolbook.com/science/tides.html - this was cobbled together in a hurry a few days ago just to settle an argument about what drives the tides. When you write programs like these, you have to get the physics right. When you're just having a conversation and expect people to focus on the important details, you can let irrelevant inaccuracies creep in while being fully aware that they are doing so - no one should be fixating on them. If I ever need to give you accurate numbers for things of specific masses being accelerated by specific forces and tell you how much the kinetic energy has changed, I can do that, but I'm not going to waste time on it when accuracy there isn't essential to the argument.

David Cooper wrote:When you write programs like these, you have to get the physics right.

Believe me, you don't. Let me tell you a bit about my background too. I did a degree in physics and then worked for a time as a high school physics teacher. I then switched careers and became a software engineer (having always had an interest in software, since the old ZX Spectrum days.) During my 20 years as a software engineer I have, among other things, worked at an educational software company writing physics simulations.

Having the ability to write software does not necessarily mean that your software is an accurate representation of a law of physics.

Playing word games isn't helpful.

The one thing I am not doing here is playing word games. I am trying to make you see that in physics words have precise meanings and if you use them sloppily then you're liable to make mistakes and be misunderstood. The word "acceleration", in physics, has a precise single meaning.

Steve3007 wrote: ↑September 6th, 2018, 6:38 pmI suspected that you might see this as a trivial point. I don't think it is a trivial point because I see it as a test of whether you know what the term "logical contradiction" means.

It's a trivial point because you're trying to present something put across as part of a conversation as something on a par with a carefully worded legal document where everything has to be right in the one place without any further interrogation being allowed to clarify the intention.

Mathematics is the language in which physics is expressed. It is a logically rigorous language. These concepts in physics are then often translated into a language like English. English is not such a logically rigorous language and it is frequently open to ambiguity and misinterpretation. If two theories are mutually logically consistent when expressed in one language (e.g. mathematics) then they must be also be mutually logically consistent when expressed in another language (e.g. English). And likewise if they are mutually logically contradictory in any language. If you've found two theories to be consistent mathematically but you think they're inconsistent when described in English, then you must have got the English wrong. Perhaps because English is prone to ambiguity.

It's all perfectly easy to establish what's meant, and you shouldn't have needed to ask. It comes down to whether the truth labels attached to the data are counted as part of the maths or not. To ordinary people, they aren't - it isn't something they recognise as part of maths. It was perfectly clear though that such labels applied to it, so all you had to do was add them and then determine that on the basis that you want them included as part of the maths, the maths of the two theories is not the same. You could then have made that technical point as an interesting side note, and that would have saved a lot of time arguing about something that has no impact on the argument that you're supposed to be trying to break.

Steve3007 wrote: ↑September 6th, 2018, 6:52 pm

David Cooper wrote:When you write programs like these, you have to get the physics right.

Believe me, you don't.

When you're up against opponents who want to tear them to pieces to show you up, you have to get them right.

Steve3007 wrote: ↑September 6th, 2018, 6:55 pmThe one thing I am not doing here is playing word games. I am trying to make you see that in physics words have precise meanings and if you use them sloppily then you're liable to make mistakes and be misunderstood. The word "acceleration", in physics, has a precise single meaning.

When I use a word with a particular meaning that's different from the one you take it as meaning, that's an issue that needs to be sorted out each time, but the point here is that it's word games when you try to impose your meaning instead of the intended one even after you've been told what the intended meaning is. You don't break the point by insisting on misrepresenting the meaning. The meaning is the one I provided and not the one you're trying to replace it with.

I just want to work out whether you're interested in studying physics. It's an interesting subject. I think you'd enjoy it.

When you're up against opponents who want to tear them to pieces to show you up, you have to get them right.

And when you make grand claims about a subject, such as that the majority of the people who have studied it are sheep following the herd who have no power of reasoning, you have to be prepared to be probed to see if you know exactly what it is that you are criticizing. People in glass houses shouldn't throw stones. I am yet to be convinced that you have studied physics. Sorry.

When I use a word with a particular meaning that's different from the one you take it as meaning...

There is one, and only one, meaning to the word "acceleration" in the context of physics. It is a vector quantity representing the rate of change of the vector quantity velocity with respect to time.

Ask yourself how I write programs like this one: http://www.magicschoolbook.com/science/tides.html - this was cobbled together in a hurry a few days ago just to settle an argument about what drives the tides.

After all these harsh words, to end the evening on a more conciliatory note: The gravity simulation that you've directed me to here looks good. I'll have a look through the source code.

Time is simply a measurement, which exists in the minds of humans. The distance an object moves through space, may be measured in time. My physical body makes one complete revolution on the surface of the Earth in 24 hours and one orbit around the sun in 365 days. These measurements make sense to humans but have no meaning to a deer living in the forest.

I have other posts in edit, but it takes more time than I have.

David Cooper wrote: ↑September 6th, 2018, 3:52 pm

Halc wrote: ↑September 5th, 2018, 8:30 amAnother heading near the bottom announces: "Note that You Can't Synchronize the Clocks in a Rotating Frame"
Well you can if the clocks are adjacent, so this is irrelevant. There is no movement you can do to a pair of clocks to get them out of sync if they're always together.

How do you synchronise them if there are adjacent clocks all the way round the circuit? If you can't do this in a satisfactory way, how can any two clocks there be regarded as validly synchronised?

You send a signal to both clocks that sets each to zero or some other common value. Since the clocks are at the same location, they get the signal at the same time in any frame.
The original statement concerned synchronizing clocks in a rotating frame where the clocks are not adjacent. But I suppose even then it could be done if both clocks are the same distance from the axis of rotation. Send the signal from that axis and they'll be synced (and stay synced) in that rotating frame, and also in the inertial frame of the rotating thing, but not in other frames. Clocks at different distances from the axis will move at different rates and have no way of being synchronized in any frame.

An example is clocks on different floors of a building, except that the higher one runs faster because it is less deep in a gravity well and that effect is greater than the dilation due to the rotating reference frame. If the day was sufficiently shorter, the two could run in sync. Pretty sure the Earth would not survive a day that short.

David Cooper wrote: ↑September 5th, 2018, 5:27 pm You can apply coordinates in whatever way you like. That will involve putting an origin somewhere and it will, for a moment, be co-moving with the Earth.

That doesn't work unless you tell the alien trying to deliver mail here where you put the origin. So tell me where you put it, and if you reference anything, tell me where that thing is first.
The impossibility of doing what I ask illustrates that we don't have an absolute location. You cannot specify an absolute location except for the big bang, and we have no coordinates relative to that. I can tell you how far we are from it (that's one of the 4 numbers needed), but not in what direction one must point from it to get here (the other 3).

My location is somewhere in the fabric of space, but the fabric of space doesn't allow us to access labels to tell us where we are within it - it keeps that knowledge to itself. We can only see some aspects of our location by comparing how we move relative to other things in that fabric.

I find pointless to posit undetectable things. Add those labels to that list. I can't get the mail delivered here by writing 'somewhere' on the envelope. Yes, we do it by comparing how we move relative to other things. Our location is relative to those other things. I see no absoluteness at all in that.

So the university textbooks teach that Einstein's relativity has been disproven??

None that I know of do, but they should.

You do realize how this makes you sound, right? I have a very controversial philosophical view, but I'm not so arrogant to say that all the texts should be rewritten to assert my personal choice, despite the fact that I arrived at the position through reason, not comfort. If on the other hand I had a scientific view that bucked the consensus like that, I would at least understand the published view, or get a job in the field since I clearly think I'm smarter than the guys getting paid to do it.
FYI, GR is beyond me. There are plenty out there that can talk circles around me. But I know my high-school physics at least, and SR isn't that hard to understand. You seem to know the math. That simulation thing, if you wrote it, is pretty impressive.

Where it becomes his assertion is when [Einstein] denies the existence of the absolute frame.

He doesn't. GR has it. Yes, it bothered him to put it back after publishing SR without the need for it. But none of SR was invalidated by that since the preferred frame is only useful on a non-local scale.

What I said is correct, and here it is again for reference: "Different frames set the speed of light relative to them to c as part of the rules as to how frames work, and that dictates everything else they do - they do not confirm the speed of light relative to themselves because they have set themselves up directly on the basis that light travels at c relative to them, and in doing so, they all assert that the speed of light relative to ALL other frames is >c in some directions and <c the other way."

I dare you to post this statement (this is what you all claim to believe) in a physics forum.

Einstein was very clear that clocks don't really run slow - they all tick at the rate of one tick per second and there is no other kind of time in the model to govern them.

That I believe is a metaphysical interpretation. He made plenty of such statements. You seem to assert otherwise. LET seems to not take a stance on this.

This exposes a contradiction in the whole model, because either it's running mode 1 with no clock running slow under the governance of any other frame's time, or there's an absolute frame mechanism which allows some clocks to run slow.

And it all works regardless of your choice of absolute frame.

No, Metaphysics is about explaining reality. Science is about making practical predictions.

Spin and hogwash.

OK, we have a serious disagreement here. There is a lot of metaphysical speculation based on the current state of physics (especially from relativity and QM), but metaphysical claims have no way to be empirically verified or falsified. If they did, the claims would be physics.

You really need to understand this distinction.

You need to understand that your physicist friends are not playing by those rules.

I don't care if my physicist friends are expressimg metaphysical opinions. The published ones usually admit to being metaphysical interpretations, such as any interpretation of QM. Yes, those get published in physics journals, but they're not presented as physics. The parts of SR that you are attacking are the metaphysical implications that are suggested by it, but not asserted by it.

Science produces useful models, and cares not a hoot if the model corresponds to reality or not.

How stupid would science be if it really worked on that basis - of course they want their theories to correspond to reality rather than being abstract stuff which doesn't make sense of things.

I don't think a model would be very useful if it didn't make sense of things.

LET has Newtonian time, and that time simply runs. It isn't a dimension. If time didn't run, nothing could happen.

Does LET assert time not being a dimension? I didn't see that. All I say was an assertion of a preferred frame. Maybe there's a better description than whatever uninformed people put in the wiki page.

I'd love to see your example. If you've got something that can change my mind, I want it.

I doubt you want your mind changed. I'm not trying to do it. I have no better truth, but I have one that's just as good.

One example I frequently use is the set of all legal chess states, a large but finite set. It has space, time, entropy, Hilbert space, and yes, causation. It doesn't have much in the way of relativity, but you can't have it all. It is a very useful model of our own universe. Anyway, I said it wouldn't change your mind, despite it having all the elements of your ordered calculator example. Each state has one prior state that must have 'happened' first, and in order, yet the set has no rate of flow, mostly because it doesn't have a current state to give meaning to that flow. Only the positing of a current state makes the positing of the flow necessary.

There's nothing more useful than finding out that you're wrong about something so that you can correct a fault in your model of reality, and unlike most people, I'm always ready to tear mine up and start again whenever that happens.

I know. Been there. I've taken up and discarded several radically different stances on things, especially in philosophy of mind. My QM stance is in its 3rd incarnation now, and for less than a year now.