Talk:Rietdijk-Putnam argument

From Wikipedia, the free encyclopedia

Contents 1 Questions 2 Name 3 Facts Disputed flag 4 Reversions - Edit war by Pjacobi

[edit] Questions

• Both names, Rietdijk-Putnam Argument and Andromeda paradox, seem not be used in scholarly writing about relativity. Can we get more evidence, that this is not a neologism we should avoid gibing an article. Isn't Relativity of simultaneity the right place for this stuff?
• Can we have other references than Vesselin Petkov, who is essentially advancing a one-person's theory of relativity, partially add odds with standard textbook results?
• What's the paradoxical about the "Andromeda paradox"?

Pjacobi 09:26, 28 September 2006 (UTC)

About the only reference: No representation is made by the archive on the accuracy or quality of preprints posted. The views and opinions expressed are those of the authors and not the Archive sponsors. With respect to the documents available from this server, the Archive sponsors make no warranty, expressed or implied, including warrants of merchantability, fitness for a particular purpose and non-infringement, and the sponsors do not assume any liability or responsibility for the accuracy, completeness, or usefulness of any information or material.

Probably that that settles it. If no good reference can be given that shows at least its notability in some way, then this article should be deleted. Harald88 19:54, 2 October 2006 (UTC)

Answers:

1. The name "Rietdijk-Putnam Argument" is commonly used in the philosophy of time. I have included a reference to the Stanford Encyclopedia of Philosophy where the extended name "Rietdijk-Putnam-Penrose Argument" is used.

2. Is relativity of simultaneity the right place for this article? I think the philosophical implications of the Argument entitle it to a separate entry although it does sit below relativity of simultaneity in the hierarchy of knowledge. Should relativity of simultaneity be put in the section Special relativity? If it should then this article should be put in the relativity of simultaneity article.

3. Other references have now been provided.

4. The Andromeda paradox is a form of the argument in which two people at the same place and instant have two different universes attached to them. It is paradoxical that for one of these people a space-admiral might be discussing an invasion whilst at the same instant, for the other person, an invasion is under way.

I hope this clears up the misgivings of Pjacobi and Harald88. These users seem to be new to the philosophy of relativity. The following links might be useful:

Persistence and spacetime http://www.phil.uga.edu/faculty/balashov/papers/polenbarn.pdf

Four dimensionalism http://fas-philosophy.rutgers.edu/sider/papers/4d.pdf

Oxford handbook of metaphysics http://www.nd.edu/~mrea/Online%20Papers/Four%20Dimensionalism.pdf

Physics in the real universe http://arxiv.org/ftp/gr-qc/papers/0605/0605049.pdf#search=

3D/4D equivalence, the twins paradox and absolute time http://www.nottingham.ac.uk/journals/analysis/preprints/McCALL.pdf

Rietdijk's work: http://www.xs4all.nl/~bcb/rietdijk30.html

Geometer 10:26, 13 October 2006 (UTC)

I've read my Reichenbach and -- just IMHO and not quotable for any Wikipedia article -- must judge, that anybody who sees a paradox in this paradox is utterly confused. The foliation of spacetime into spacelike planes and time line is completely conventional. And no point in the elsewhere (neither in fwd nor in bwd light cone) Minkowski diagram can claim to be more simultaneous than another. --Pjacobi 10:30, 13 October 2006 (UTC)

Hi there. It was Penrose who called it a paradox. I also think it is bog standard SR but the consequences are philosophically profound which is why it has been discussed in a couple of hundred philosophical papers and deserves an entry. The alternative is Presentism which is the normal idea of time amongst people who are unaware of relativity. Geometer 10:34, 13 October 2006 (UTC)

As much as I otherwise like the Stanford Encyclopedia of Philosophy, that article is rather bad:

This is an odd situation indeed. An event in Bob's future seems in some way to become fixed or inevitable by being in Alice's past.

Ouch, everything outside your forward lightcone (which is independent of your velolicity, so it conincedes for Alice and Bob), is fixed and inevitable because nothing you can do now or in the future can have any effect there.

Pjacobi 10:45, 13 October 2006 (UTC)

The problem here is that the Stanford Encyclopedia is an encyclopedia of philosophy. Philosophers think that the relativity of simultaneity is "odd" because it suggests a block universe where concepts such as free will are questionable. But this is not really part of Rietdjik-Putnam where it is just pointed out that relativity implies that the universe really is four dimensional. ie: if special relativity is true then the universe is 4D. Geometer 15:23, 13 October 2006 (UTC)

The question whether the physics imply determinism and realizing that no spacelike hypersurface is more "present" than any other is orthogonal. --Pjacobi 21:47, 15 October 2006 (UTC)

[edit] Name

The names Rietdijk and Putnam occur only in the title. At the very least, to be in accordance with the Manual of Style, the article should begin in a fashion like this: "In late-night discussions on special relativity, the Rietdijk-Putnam argument is the argument that ...". That is, we need to see the name of the article back in some context. Then the name needs to be explained: "The argument is named after Penrose's two dogs, Rietdijk and Putname, who happened to be walking in opposite directions when he conceived of the argument." I'm not sure the references given meet the criterium of being reliable sources. -- --Lambiam^Talk 15:56, 28 September 2006 (UTC)

Your problem of sources is now answered. The problem of whether or not the world is a nD manifold is central to physics. Why are you insulting such eminent scientists and philosophers as Penrose, Putnam and Rietdijk? Geometer 10:26, 13 October 2006 (UTC)

[edit] Facts Disputed flag

I removed this because the facts were not disputed, Pjacobi wanted more explanation. Please provide it. The article agrees with what Pjacobi has said:

"Ouch, everything outside your forward lightcone (which is independent of your velolicity, so it conincedes for Alice and Bob), is fixed and inevitable because nothing you can do now or in the future can have any effect there."

But remember that this article is a description of the existence of the argument, it is not an attempt to argue for Stein's counter argument or even to argue for Putnam etc. Please explain what is factually incorrect about the article. If the article does not summarise Rietdijk, Putnam and Penrose's positions correctly then it should be put right. Geometer 15:16, 13 October 2006 (UTC)

If you want to handle this more specifically, we can do it sentence by sentence. The first sentence:

• If special relativity is true then each observer will have their own plane of simultaneity that contains a unique set of events that constitute the observer's present moment.

contains one misunderstanding and implies another. If it can be sourced, it must be attributed to someone specific. --Pjacobi 21:47, 15 October 2006 (UTC)

If, as you suggest, you know how to correct this sentence, please do so. Please edit rather than placing a "factual inaccuracy" flag on the article! I am removing the flag in anticipation of your edit. Geometer 08:14, 16 October 2006 (UTC)

Sorry, I don't have read the original articles giving this argument. All I can say, is that the exposition of their ideas in this article indicate a misunderstanding or a heterodox interpretetation of relativity. The best I can do, would be either to expose the orthodox view, but this would duplicate the article Relativity of simultaneity or propose it for deletion -- or ask you to address the raised the concerns. --Pjacobi 08:20, 16 October 2006 (UTC)

'This article is about the Rietdijk-Putnam argument, not about whether the argument is true or false.' Opinions on the truth or falsity of the argument would be original research. Geometer 08:26, 16 October 2006 (UTC)

For this reason, statements that contradict orthodox interpretations of SRT have to be attributed. --Pjacobi 09:00, 16 October 2006 (UTC)

[edit] Reversions - Edit war by Pjacobi

Nastyyy.. I only wanted to add an article to explain an interesting area of philosophy. I hate this edit warring business. I am out of here. Bye Geometer 08:26, 16 October 2006 (UTC)

For heavens sake, I've removed the tag, without my concerns answered. But you're the best candidate to enhance this article. --Pjacobi 09:07, 16 October 2006 (UTC)