D1: If one frame says something is stationary and another says it's moving, it is clearly impossible to tell whether something is moving or not, so your objection to that one is frankly ridiculous.
S1:Which is perhaps one reason why frames don't say that. Movement is defined as the change in the spatial distance between two objects with respect to time. So, if you use the correct definition of the word "moving", clearly we can work out if we're moving.
D2: Frames do say that. You can measure movement in any way you like, but if something is not moving in one frame (no change in spatial distance between itself and any other object at rest in that frame) and is moving in another (with a change in spatial distance between other objects which are at rest in that frame), then we have contradictory claims from different frames about whether the object is moving or not, and we can't tell which one is wrong.
S2a: A reference frame is simply a set of coordinates. It can be simply visualized by imagining a ball with X, Y and Z axes sticking out of it at right-angles to each other. A lump of clay and three rulers. That ball is stationary with respect to that reference frame. The movements of other objects can be measured with respect to that reference frame. Other reference frames (other lumps of clay with rulers sticking out of them) can be moving relative to that reference frame.
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S2b: So what David is saying in the part of the above quote which I have highlighted in bold is that if I measure the movement of a single object with respect to two different reference frames that are moving relative to each other, the different results that I get constitute "contradictory claims" and "we can't tell which one is wrong".
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S2c: This is the same as saying that If I am driving in a car, and if I make the observation that I am stationary with respect to the car but moving with respect to the road, I am making contradictory claims, one or both of which must be wrong.
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S2d: I disagree.[/quote]
D3: It's not the same as that at all. Something more equivalent would be the following claim: if I'm driving in a car and make the observation that I'm stationary with respect to the car, and also stationary with respect to the road, but that the car is moving along the road, I am not making contradictory claims.
Steve3007 wrote: ↑September 21st, 2018, 1:44 amDavid, look properly at what you've said here and what you've said in the part of the above post that I highlighted in bold [D2]. Look at the meanings of the sentences. The example you've given in the quote immediately above, in your most recent response, clearly does contain a contradictory claim because it says something completely different from the part I highlighted in bold earlier. In this more recent example, there's a claim to be both moving and stationary with respect to the road. Obviously that's a contradiction.
D1 says that you can't tell if you're moving or not because different frames make contradictory assertions (about the underlying reality) and you don't know which are true. S1 then tries to change the definition of the word "moving", and D2 shows that it makes no difference to the meaning. In S2b, what you say is correct, but we're interpreting it in different ways. You're reading from it that the claims about what the claims are are not contradictory (and I agree with that), while I'm reading from it that there is a contradiction between the claims that are being discussed - this all depends on how you interpret the part that says "the different results that I get".
You produce an example with no contradiction in it in S2c, so in D3 I show you a replacement for your example that would actually contain a contradiction. D3 is more equivalent in that it contains a contradiction, whereas your example doesn't. My replacement doesn't fit with any real measurements, but it isn't there to illustrate an example of something that does - it is simply there to show what a real contradiction looks like. I then went on to provide a better example of the kind of contradiction that does apply to this stuff in which I compared the speed of light relative to objects which are moving relative to each other, and that was the best place to take it because the clearest way to illustrate the difference between stationary and moving objects is to look at the speed of light relative to them.
I can see now though that you hadn't taken on board what I said the last time this came up (with Halc, if I remember rightly), so it seems that I need to go through it again for you. If one frame says something is stationary and another frame says it's moving, there is no contradiction in the claim that one frame says the object is stationary and the other frame says the object's moving. There is a contradiction though between the claims being discussed: one frame says the object's moving and the other says it's stationary, and it isn't possible for both of those claims to be true. You can word it in different ways to make subtle differences in meaning: frame A says the object's stationary relative to frame A and frame B says it's moving relative to frame B, and with this careful wording there is no direct contradiction - the contradiction is then hidden on another level which only shows up when you ask if it's moving or stationary in the underlying reality. Whether you read the word "moving" in one way or the other depends on whether you're applying a bias to it, and you're applying an SR bias. You could accuse me of applying an LET bias to the same word, but when we look at the issue of the speed of light relative to the two objects, LET says they cannot both be c in all directions relative to both objects. SR is normally taken to say that it is c relative to both objects in all directions, and that is another aspect of the exact same SR bias. If you reject that SR bias (the SR dogma that you disown) and want to allow the speed of light relative to the objects to be different, then you are accepting the LET "bias" and by extension the underlying reality that you don't want to accept - you are then logically forced to interpret the word "moving" the LET way.
Now look at the bolded quote from you. I'll break it down for you into easy chunks:
If something is not moving in one frame (no change in spatial distance between itself and any other object at rest in that frame)...
i.e. if a measurement with respect to frame 1 indicates no movement with respect to that frame.
...and is moving in another (with a change in spatial distance between other objects which are at rest in that frame),...
i.e. if a measurement with respect to frame 2 indicates movement with respect to that frame.
...then we have contradictory claims from different frames about whether the object is moving or not, and we can't tell which one is wrong.
i.e. if something is measured as stationary with respect to frame 1 and moving with respect to frame 2 then you claim that there is a contradiction.
No: you're just looking for the contradiction in the wrong place. The claims have contradictions tied up in them as the two frames are both theorising about the nature of the underlying reality, and they cannot both be correct in their description of it. Frame A claims that the object is stationary in the underlying reality, and frame B claims that it is moving in the underlying reality.
This is precisely the same as saying that if I observe myself to be moving with respect to the road but stationary with respect to my car, then I am contradicting myself. As I said earlier.
You seem to be incapable of seeing the meaning of your own utterances.
No - the issue is that you can't recognise the subtle differences in meanings. If I reword your example, I can put the clear contradiction into it like this: If I observe myself to be moving with respect to the road AND take the road to be stationary in the underlying reality, but I observe myself to be stationary with respect to my car AND take the car to be stationary in the underlying reality, then I am contradicting myself.
The contradictions are found when you consider different frames to be attempting to provide accurate descriptions of the underlying reality. Your SR bias predisposes you to ignore the need for an underlying reality, so you are largely blind to it.
David, you accuse others of "lacking the necessary expertise in logical reasoning" yet you don't seem to be able to understand the logic of a simple set of sentences that you yourself have written. As a result, it's impossible for me to even tell what you actually think.
As always, you are the one who is missing the crucial part of the picture. You're trying to make out that I'm calling things contradictions that (quite genuinely) aren't contradictions, but you're failing to see the actual contradictions that I am pointing to.
So please, will you correct this:
David Cooper wrote:Frames do say that. You can measure movement in any way you like, but if something is not moving in one frame (no change in spatial distance between itself and any other object at rest in that frame) and is moving in another (with a change in spatial distance between other objects which are at rest in that frame), then we have contradictory claims from different frames about whether the object is moving or not, and we can't tell which one is wrong.
so that I can work out what you actually think is going on when somebody measures their velocity with respect to a reference frame. Because right now, I don't know.
There is nothing there needing correction other than your reading of it. It might help you though if I word it like this:-
If something is not moving in one frame and is moving in another, then we have contradictory claims from different frames about whether the object is moving or not
in the underlying reality which both frames are attempting to describe and we can't tell which is wrong.