Why in the world would Einstein suggest....

@layman,

SR DOES NOT require anyone to assert that he is motionless. That's an incorrect understanding of it. Where did you got that?

Look, you can try and find holes in relativity all you want, but I'm no game. The twins 'paradox' has been explained here and we all agreed on the explanation... I do not understand everything about it and the relativity of simultaneity is certainly puzling on an intuitive level, but many things are in modern physics...

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@fresco,

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The irony is that this came from Einstein, himself a scientific realist !

LOL. Do you know many scientists who are not realist? What are they studying?

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@Olivier5,

I have had recourse recently to refer to "Arguing abut Science" (Bird and Ladyman 2011). This is a compendium of papers with part nine devoted to "scientific realism and anti-realism". In particular there is an interesting paper by Van Fraassen describing "constructive empiricism" as an alternative to "realism".
You might try this ....
http://plato.stanford.edu/entries/constructive-empiricism/
....if interested.
BTW this quote by him....

Quote:

Science aims to give us theories which are empirically adequate; and acceptance of a theory involves as belief only that it is empirically adequate. (1980)

.....has been endorsed by physicists such as Feynman and Hawking.

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@fresco,

Seems like casuistry to me. Empiricism implies that reality acts as the referee to our theoretical musings.

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@Olivier5,

Perhaps. But as I understand it casuistry seems to refer to individual cases, whereas constructive empiricism involves paradigmatic clusters.Yet since casuistry is not in my active lexicon I would not comment further.

As discussed before, I am quite happy to accept Rorty's dismissal of any "realism" issue in favour of the neo-pragaticists' axiom of "accept what works". This is not completely sufficient for acceptance of a theory because (1)"elegance" is recognized as a major criterion. Note also that "empiricism" needs a focus to define what constitutes "data" such that (2) another criterion of theory acceptance is "generation of new data".

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@Olivier5,

Quote:

SR DOES NOT require anyone to assert that he is motionless. That's an incorrect understanding of it. Where did you got that?

The Harvard physics professor cited in the following link says otherwise, Oliver, as does every other physicist I'm aware of. So, I see (at least one) source of our disagreement.

Just think about it. Let's use the twins. Under the protocols of SR is the travelling twin ALLOWED to acknowledge that he is the one moving? If he was, then, as between the two, he would use the EARTH'S frame of reference (not his) to calculate the state of affairs. SR does not allow this. He must use "his" frame, which posits himself as an absolutely motionless point, and all further calculations by him proceed from there.

Quote:

Look, you can try and find holes in relativity all you want, but I'm no game.

You obviously do NOT understand the implications of the relativity of simultaneity. From the sounds of it, you don't care to understand. Your choice.

http://able2know.org/topic/265997-22#post-5887657

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@fresco,

I meant casuistry as splitting hair, making distinctions without differences. Empiricism implies that the data is what ought to decide between two competing theoretical claims. That data can be focused by theory but whether Abdul or Abdel (or Paul or Peter) collects the data ought to make no difference to the data. At least that is so in natural sciences. That gives a certain objectivity of sorts to data, in any empirical view. I don't see how empiricism qualifies as the opposite of realism.

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@Olivier5,

Quote:

I don't see how empiricism qualifies as the opposite of realism.

It doesn't. I'm not sure where you got from. "Scientific realism" is about a search for "underlying truth". Empiricism is about consensual observation.

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@layman,

Another physicist on the topic of "who's moving," Oliver:

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It is important to realize that it really is the case that each of these people measures the other's clock as running slowly. So who is really running slowly? So long as both remain within their fixed inertial reference frames, the answer is relative and always the other guy.

http://www.astro.virginia.edu/~jh8h/Foundations/quest7.html

It's really not so "relative" after all if it's ALWAYS the other guy moving, is it?

If his frame is "equivalent" to mine, then why can't I use HIS frame for my calculations?

Dr. Morin from Harvard, previously cited, gives the answer: It would destroy the theory, which is absolutely dependent upon two observers asserting contradictory and mutually exclusive propositions.

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@layman,

You do understand it well enough. Layman continues to cite a chapter which he has not read properly.

And with respect to the "new data" factor, it appears that it was Einstein himself who introduced "the twin paradox" scenario. Without his predictions we would not be having this conversation.

This thread will continue to go round in circles because layman has a vested interest in pushing his minority view. I suspect that he has tried pushing it on a physics forum to no effect. We seem to be stuck with providing accommodation for a refugee

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@layman,

Where or where does this guys says that one is obligated to think of oneself as immobile???

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@Olivier5,

Quote:

Where or where does this guys says that one is obligated to think of oneself as immobile???

It is always the other guy's clock which runs slow (assuming inertial frames), and it is always the moving clock which runs slow. Do the math there.

Quote:

A commonly heard phrase in the realm of special relativity is "Moving clocks run slowly". But—even in the context of special relativity—is it always true? The answer is no. It's only true when a clock's ageing is measured in an inertial frame. This assumption of inertiality might not always be stated explicitly in textbooks, but it's always there.

http://math.ucr.edu/home/baez/physics/Relativity/SR/movingClocks.html

Reordering the words: "when a clock's ageing is measured in an inertial frame [it is always true that] Moving clocks run slowly"

The very notion of a (non-accelerated) frame of reference presupposes motionless.

Of course this same requirement cannot be imposed on accelerating frames, because SR must acknowledge that accelerating motion is ABSOLUTE motion. A person in an aceelerating frame will see HIMSELF as moving (as will anyone else observing him from an inertial frame).

If Al passenger on the train (OP) had simply said: I remember buying my ticket. I remember accelerating. I knew I was moving then. I know the law of inertia. I must be moving now..

And then calculated accordingly, then there would be NO SR. He can't agree, if the speed of light is to be deemed constant in all frames. So, Al makes him assume he ISN'T moving. This notwithstanding the fact, that, in this very example, uses the fact that he is moving to explain why the lightning strikes are not simultaneous "for him>"

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@fresco,

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Without his predictions we would not be having this conversation.

Lapsing right back into the realist view you pretend to detest, eh, Fresco?

Without the LORENTZ TRANSFORMATIONS, which Al took from Henrik Lorentz, Al would "predict" nothing.

Of course those formulas were developed by Lorentz to be used with precisely the opposite assumption, i.e., that simultaneity is absolute, not relative. To this day, his theory (of motion, not of the ether, per se) makes every single prediction that SR does. I wonder why.

Lorentz also predicted that "moving clocks run slow." He just didn't say that there is an infinite number of places in the universe (inertial frames of reference) which are ALL motionless.

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@fresco,

Quote:

This thread will continue to go round in circles because layman has a vested interest in pushing his minority view. I suspect that he has tried pushing it on a physics forum to no effect. We seem to be stuck with providing accommodation for a refugee

sorry to say, but this is extremely illogical.

First of all a minority vieuw doesn't say a thing. It is the popularity fallacy.
and second it doesn't say one bit if he had no effect on a physics forum.
That can mean that those people are stubborn and can't think which is the case with most scientists.

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@fresco,

Quote:

Quote:
I don't see how empiricism qualifies as the opposite of realism.

It doesn't. I'm not sure where you got from. "Scientific realism" is about a search for "underlying truth". Empiricism is about consensual observation.

Consensual observation of... ? And by ... ? Let's flesh this out. You will see that the underlying assumption of empiricism is dualism.

The search for a final scientific truth is better called 'scientific idealism' or 'literalism' because it presupposes the existence of ideas (real laws) organizing reality, 'as opposed to scientific pragmatism which does not assume that reality is ultimately understandable, and just makes do with what works.

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@fresco,

Quote:

This thread will continue to go round in circles because layman has a vested interest in pushing his minority view.

"Minority view?" It is virtually unanimously acknowledged that an AST (absolute simultaneity theory) is empirically indistinguishable from SR. The majority here seem to emphatically reject that known fact. For them SR in the ONLY explanation and it is sacrosanct.

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@layman,

This is true,

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@layman,

What happened to your Harvard Prof's answer to Olivier's question ? All we got was a few selected lines from a relativity primer ?

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I wonder why.

Lorentz sketched the differences between his results and that of Einstein as follows

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... "the chief difference [is] that Einstein simply postulates what we have deduced, with some difficulty and not altogether satisfactorily, from the fundamental equations of the electromagnetic field. : The chief cause of my failure was my clinging to the idea that the variable t only can be considered as the true time and that my local time t' must be regarded as no more than an auxiliary mathematical quantity. In Einstein's theory, on the contrary, t' plays the same part as t; if we want to describe phenomena in terms of x', y', z', t' we must work with these variables exactly as we could do with x, y, z, t."

Try doing a bit of reading for a change.

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@fresco,

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What happened to your Harvard Prof's answer to Olivier's question ?

What's your question. Dr. Morin's assessment is quite clearly stated.

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@fresco,

You are obviously quoting Lorentz, Fresco, and I am familiar with his views.

Any reason you didn't include your source? Do you have one.

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Why in the world would Einstein suggest....

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