To speak to another with consideration, to appear before him with decency and humility, is to honour him; as signs of fear to offend. To speak to him rashly, to do anything before him obscenely, slovenly, impudently is to dishonour. Leviathan, X.

Proverb for the year: if you have nothing new to say, don't say it.

You are welcome to leave messages here. I will reply here (rather than on, say, your user page). Conversely, if I've left a message on your talk page, I'm watching it, so please reply there. In general, I prefer to conduct my discussions in public. If you have a question for me, put it here (or on the article talk, or...) rather than via email.

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My Contribs • Blocks • Protects • Deletions • Block log • Count watchers • Edit count

I know that you were disappointed by the conduct and results of the case, and I'm sure you're aware that I voted against most of the remedies proposed against you and share some portion of your feelings. However, I respectfully suggest that calling one of my colleagues a "fool" on-wiki is not helpful. We all accept a great deal of criticism and commentary as par for the course in connection with serving as arbitrators—just as you have as one of our active administrators on contentious topics—but I always still think it's better, and more effective, to stay away from the overtly ad hominem. Regards, Newyorkbrad (talk) 13:35, 12 September 2009 (UTC)

Ah, you've found it :-). And while you are here, thank you for your votes. I am indeed deeply disappointed by the conduct of your colleagues; and I regret having to disappoint you now. Arbcomm are big boys and girls and can cope with some discrete criticism of their actions. Moreover, you (arbcomm, I can't recall how you personally voted) established the principle that users are entitled to insult a blocking admin as much as they please on their own talk pages; I'm sure you'll extend a similar privilidge to those who desysop people William M. Connolley (talk) 13:40, 12 September 2009 (UTC)

I should add that there is a diff there justifying the appelation. I regard the extensive comment re the cabal as being grotesquely stupid. However this carries no implication that is the most foolish thing that particular arb has done in this case William M. Connolley (talk) 17:01, 12 September 2009 (UTC)

Nobody is entitled to insult anyone here William. If arbcom has passed some sort of rule the "entitles" users to insult a blocking admin(and I seriously doubt they have) then I would use good sense and ignore such an "entitlement" as unproductive. Chillum 14:11, 12 September 2009 (UTC)

Really? Are you certain of your ground here? Suppose someone were to call the arbcomm "liars" or "lying bastards" or "ridiculous" or "devious" or compare them to a third world Junta? Do you think that would be actionable? William M. Connolley (talk) 17:01, 12 September 2009 (UTC)

I think it would be rather poor judgment. Just because something is not actionable does not make it an entitlement. Chillum 17:46, 12 September 2009 (UTC)

If you mean the arbcomm's decision permitting this, I entirely agree with you. However, until they are wise enough to revoke it (and alas I fear we will have rather a long time to wait for wisdom from them) we are stuck with it William M. Connolley (talk) 17:49, 12 September 2009 (UTC)

I haven't looked to see which arb was accused of being a "fool," but am curious how would "Stephen Bain should not be entrusted with anything more valuable than a ball of string" would be received. I'd like to know before I say that. Short Brigade Harvester Boris (talk) 14:34, 12 September 2009 (UTC)

This arbitration case has been closed, and the final decision is available in full at the link above.

As a result of this case:

1. The cold fusion article, and parts of any other articles substantially about cold fusion, are placed under discretionary sanctions.
2. Abd (talk · contribs · deleted contribs · logs · filter log · block user · block log) is banned for a period of three months from Misplaced Pages, and for a period of one year from the cold fusion article. These bans are to run concurrently. Additionally, Abd is prohibited from participating in discussions about disputes in which he is not one of the originating parties, including but not limited to article talk pages, user talk pages, administrator noticeboards, and any formal or informal dispute resolution, however not including votes or comments at polls. Abd is also admonished for edit-warring on Arbitration case pages, engaging in personal attacks, and failing to support allegations of misconduct.
3. William M. Connolley (talk · contribs · blocks · protections · deletions · page moves · rights · RfA)'s administrator rights are revoked. He may apply for their reinstatement at any time via Requests for Adminship or appeal to the Committee. William M. Connolley is also admonished for edit warring on Arbitration case pages.
4. Mathsci (talk · contribs · deleted contribs · logs · filter log · block user · block log) is reminded not to edit war and to avoid personal attacks.
5. The community is urged to engage in a policy discussion and clarify under what circumstances, if any, an administrator may issue topic or page bans without seeking consensus for them, and how such bans may be appealed. This discussion should come to a consensus within one month of this notice.

On behalf of the Arbitration Committee,

Hersfold 22:58, 13 September 2009 (UTC)

I'm am sorry to see that your adminship has been revoked. I believe that our circumstances are similar in a way. I too was once an admin and lost my tools mainly due to conflicts on articles related to the events surrounding the 9/11 attacks. I know that the vast majority of my content creation and all my FA's were done after I was desysopped...with that said I am hoping that we can still look forward to your wisdom and guidance in those areas you have so instrumental in and that you will continue to help us build as reliable a reference base as we can achieve. Best wishes to you!--MONGO 03:24, 14 September 2009 (UTC)

Not a great day for Arbcom or the project. However I doubt you will take it too personally. --BozMo talk 08:39, 14 September 2009 (UTC)

Thanks to you both William M. Connolley (talk) 22:25, 14 September 2009 (UTC)

I ask that you please accept my nomination to regain your administrative rights at RFA. 99.191.73.2 (talk) 13:23, 14 September 2009 (UTC)

Vair tempting. I fear that was the wrong forum. I shall ponder this matter William M. Connolley (talk) 21:26, 14 September 2009 (UTC)

I'm sorry to hear this, William. You were a good admin. I hope you won't let it bother you. SlimVirgin 00:24, 15 September 2009 (UTC)

I rarely comment in RFA, nor do I monitor them. If you ever decide to be re-nominated, I would appreciate a courtesy notice as otherwise I will almost certainly not be aware of the discussion. WLU (t) (c) Misplaced Pages's rules:/_complex 16:45, 15 September 2009 (UTC)

Interesting

Hardly surprising that arbcom wants to keep their mess as far from view as possible. Short Brigade Harvester Boris (talk)

Weird. Who is it supposed to be a courtesy too? I've asked C User_talk:Carcharoth#CB. Certainly it seems to me that the people most embarassed by that page would be arbcomm William M. Connolley (talk) 07:17, 15 September 2009 (UTC)

Woonpton expressed a desire for blanking, both during the case and at WT:AC/N. As I understand it, she feels that having Abd's allegations about cabal-ism visible were and are slandering her and everyone else smeared by the accusations. EdChem (talk) 07:25, 15 September 2009 (UTC)

You might also want to look at User_talk:Cool_Hand_Luke#Thanks_and_question for more on Woonpton's view, as well as the thread immediately above it. EdChem (talk) 08:09, 15 September 2009 (UTC)

This giant spwaling ill-managed case now extends to Wikipedia_talk:Arbitration_Committee/Noticeboard#Courtesy_blanking_of_case_pages. Sigh - I thought they had finally managed to finish this case, but not, they drag its stinking corpse out of the grave and prop it up again William M. Connolley (talk) 08:40, 15 September 2009 (UTC)

Not sure which section is best to post this, but I would be delighted to renominate you at RFA or support you if you decide to run. Stifle (talk) 16:32, 15 September 2009 (UTC)

Various people have been kind enough to ask me to run for admin, so that they could vote for me. Some have been unkind enough to ask me to run, so they could vote against. But certainly it would be a way to clear the air. The obvious disadvantage (apart from the even more obvious one of letting the std.malcontents vent their bile) would be that quite a few honest folk would simply say "not so soon after arbcomm sanction" out of respect for arbcomm. Or so I suspect.

Anyway, here is your chance to offer wise advise. Be brief or be truncated. Be helpful or be removed. This isn't a vote. I will clean up "mess" as it goes when I can.

William M. Connolley (talk) 21:13, 17 September 2009 (UTC)

Do it

• Yo.  pablo_hablo. 21:17, 17 September 2009 (UTC)

• Support. Hell In A Bucket (talk) 21:37, 17 September 2009 (UTC)

• IMO, Misplaced Pages needs people like you as admins. If you do go for it and it doesn't work out, I think you should try again later. When I saw what happened I immediately assumed that it was only temporary as the correct action would eventually be taken. OlYeller 16:56, 18 September 2009 (UTC)

• Go for it. You've, on the whole, done far more good than bad. Jtrainor (talk) 06:02, 21 September 2009 (UTC)

• It's a bit late, I realise, but then I came to all of this a bit late. My answer is: for the good of Misplaced Pages, you should be an admin again at some point. Also, please see my answer under "Don't". --Merlinme (talk) 20:48, 14 October 2009 (UTC)

Don't

• Why create drama? -GTBacchus 21:19, 17 September 2009 (UTC)
• It'd almost certainly end up like Misplaced Pages:Requests for adminship/MZMcBride 2 with the std.oppose being "wait a while". -Atmoz (talk) 21:24, 17 September 2009 (UTC)
• You'll like not being an admin. Trust me. Give it a while. Short Brigade Harvester Boris (talk) 21:31, 17 September 2009 (UTC)
• While it's not quite the same as MZM2 which was run during the arb case, it is quite soon after. Some might see it as thumbing your nose - I wouldn't - but I think you'll get opposes just for that so giving it a while would be worthwhile. Might be healthy to reflect and take a break anyway. –xeno 21:34, 17 September 2009 (UTC)
• It's up to you, and I'd support your run, but it may not be the right time. More below, to keep this short. TenOfAllTrades(talk) 21:47, 17 September 2009 (UTC)
• Don't do it yet. Though I would support you wouldn't pass and it would just be a drama-fest. Protonk (talk) 01:36, 18 September 2009 (UTC)
• I suspect that the planets will be more favorably aligned a little over three months from now. N p holmes (talk) 05:30, 18 September 2009 (UTC)
• Strangely also I think waiting a little is better. Making it a sort of snub or vote of no confidence on Arbcom would be fun but it might prevent all sorts of good people from supporting you, and confuse the issue that we all want you back as admin but we may not think humiliation for even a weak Arbcom is in the community interest. For example I think you should offer NewYorkBrad as the Arbcom member who actually read everything the honour of nominating you, and etiquette would prevent that without a decent pause. Waiting three months and expressing some sort of regret is more likely to give the best outcome, which is you doing your important role with strong support from the whole community apart from a few sad souls (as before). If you do stand you need to count to ten on answering questions by the way cos you've been feeding the Trolls too much of late ;) --BozMo talk 13:07, 18 September 2009 (UTC)
• I'd recommend wait, just so people don't go around saying you have no respect for wikipedia, or bill it as a no confidence vote in arbcom (we saw how they reacted to that one with the FT2 fiasco). However, I will vote for you now or later - unless you block me again. I will also vote against ArbCom if given the opportunity, ArbCom is clearly broken, but they should be separate. How about you all vote for me instead? Verbal chat 15:08, 18 September 2009 (UTC)
• Is there any conceivable way that you could avoid contentious areas or subjects for three months? Cases are not always decided based on the pure merits, because many people are using a 20,000-foot view and don't have time to look at every diff. The grand-overall-average view of your work is probably that you tackle many difficult issues, and often act forcefully. Credit for the good may be diluted by not fully understanding what it is that you do. Arbcom may be deciding based on the 'often act forcefully' rather than the judgment that has gone into your actions. EdJohnston (talk) 18:40, 19 September 2009 (UTC)
• Don't bother - adminship isn't worth it any more (and I speak as someone who was an admin for six years). It'll make you the target of cranks and thugs on- and off-wiki, as I'm sure you've already found, and you won't get any backup from an Arbcom dominated by dim-witted wannabe politicians who are more interested in posturing than in promoting the development of a high-quality encyclopedia. I suspect that you will be able to be more effective without adminship, to be honest. -- ChrisO (talk) 22:20, 19 September 2009 (UTC)
• If someone snatches away your mop, it might be a good invitation to move on to activities that are more enjoyable than volunteer janitorial work. Awickert (talk) 01:10, 21 September 2009 (UTC)
• For your own sanity, it's probably best to avoid for a while. I'm speaking as someone who's given up responsibility I'd volunteered for (in a different context) and loved the freedom afterwards. Let someone else take that pain for a while. At the point where you think: "They're doing it all wrong. But the only way it's gonna get done right is if I do it. Ah, what the hell. Once more unto the breach, dear friends"; at that point, maybe consider it again. But not earlier. --Merlinme (talk) 20:54, 14 October 2009 (UTC)

Extended commentary

(feel free to delete this extended section) I'm gobsmacked by Thatcher's recent claims of your involvement and misuse of tools, and I'm concerned that until that gets straightened out it's going to torpedo you. (I thought it was No Big Deal to semiprotect or even protect a page – even a page that you frequently edit – if it is being extensively targeted by sockpuppets or vandals. Obviously any sort of protection to 'win' a content dispute is out, but doing to it to stop block evasion and vandalism should be a legitimate use of the tools.) I'm also concerned that some people will treat the RfA as a referendum on the ArbCom — which cuts both ways for you. (Contrary to GTBacchus, I wouldn't see you as using this as a vehicle for vindication; you genuinely do (or have done) an extremely large amount of useful admin-type stuff which does help the project, particularly at AN/3RR.)

Cynically, I also note that waiting until Abd returns and casts his verbose vote against you might help to persuade fence-sitters that your actions were an understandable response — though a reference to his evidence presentation during the arbitration, or to any old version of Talk:Cold fusion, might suffice in that regard.

Finally, it may be useful to wait until after the concerns about the seriously broken process followed during the arbitration are presented and the ArbCom offered a chance to explain and defend their actions. Editors are likely to be more sympathetic to your candidacy after a bit of cool reflection, examination, and hindsight reveal to the community just how badly they screwed up (in terms of process, and not just outcome). If they stonewall or gloss over rather than acknowledging and fixing their errors, it further helps your case. TenOfAllTrades(talk) 21:47, 17 September 2009 (UTC)

Goodness, I struck it. Shall I beat my breast publicly? I screwed up. -GTBacchus 21:49, 17 September 2009 (UTC)

Sorry; I got an edit conflict when I posted my extraordinarily overlong comment — I didn't realize that there had been a teapot tempest while I was typing. Consider my comment modified to reflect your new statement — even if you wouldn't see a run so soon as a vehicle for vindication (in lieu of encyclopedia improvement), I wouldn't be surprised to see a few objections on that basis. TenOfAllTrades(talk) 22:01, 17 September 2009 (UTC)

(you're still free to delete if you want) Personally, I don't have much trust left after this final ArbComm, I see yet more editors leave Misplaced Pages because of the total mismanagement, etc. etc. I am not going to give do or don't advice. You have my support, strong support (I already watchlisted the page). I do fear the concerns of others above, it will be trolled by your opponents (but those will do that anyway), regulars will fear the Arb.Comm. decision, and I think you need a strong case. I would be delighted to see you pass, so soon after the closure, it would be a proof that the decision of the ArbComm was totally wrong, that you have wide support for your actions and decisions, and it would strengthen a case against ArbComm to show that they did loose touch with reality. Though I hope, I do not see any chance that they will acknowledge, let alone repair their errors. Maybe they will adapt from now, but it is too late. --Dirk Beetstra 22:01, 17 September 2009 (UTC)

Regarding , you are quite welcome to raise any of your concerns or points on my talk page. I'm quite open to constructive feedback, even if it's harsh or drastically opposed to my views or actions. I even promise not to seek a block if you call me a fool. However, if you call me Mungojerrie or make me listen to "Memory", it's war! :-) (If you prefer to keep everything together, we could easily have the same discussion at User talk:William M. Connolley/For me/Misc arbcomm-y stuff.) Vassyana (talk) 14:42, 24 September 2009 (UTC)

Thanks. I'll decline your permission to call you a fool on your page, though, since I think that would be wrong. The "Misc" page needs some more work when I hve a spare moment William M. Connolley (talk) 14:49, 24 September 2009 (UTC)

I am mostly interested in what you find most troublesome about my statement and what harm you think it would bring if taken to heart. It is entirely possible that there is a misunderstanding or that I simply communicated ineffectively. Even if it is the simple fact that our opinions are on opposite poles, it would be valuable for me to better understand your concerns. I'll keep an eye on the subpage and remain available for discussion. Vassyana (talk) 14:59, 24 September 2009 (UTC)

I thought some of your decisions were described as foolishness. This is not in my view the same as calling you a fool. Everyone makes foolish decisions and sometimes takes foolish actions. Criticising an action as foolish IMHO is not a personal attack whereas calling the actor a fool is. As for the troublesome statement the problem I have with it is "Fernseeds and elephants" (roughly that you are staring out of the window discerning a fern seed in the distance when there is an elephant in the room, to paraphrase CS Lewis) you say "there is certainly a kernel of truth to the concerns in that there is a certain indentifiable group that appears to act in a mutually supporting fashion" completely misses the bigger problem which drives people with nothing more in common than a basic understanding of science to "appear to act in concert". On most ordinary differentiators (religion, politics, hair length, social class?) I am opposites to WMC (we do both have kids I think) but he has a scientific training of sorts and D Phil in maths from the one of the better universities in the UK and a background in scientific modelling, and I have good scientific training, a PhD from the better place and a background in scientific modelling and that means when faced with utter rubbish (someone who thinks that Global Warming violates the second law of thermodynamics) we tend to agree. So perhaps it is a concern to you that there is an appearance of a Cabal but there is also a concern in the appearance of idiocy on some of the groups who attack. You say "commonly overwhelmed by involved opinion and regularly featured involved editors !voting and/or commenting as though they were uninvolved users providing an opinion" but when I look I see five or six identifiable anti WMC anti science editors who never miss an opportunity to express a view and perhaps fifty scientifically trained editors who each take a turn for a few months patiently explaining to these people and then move back to the middle of the penguin huddle. A lot of the antogonists I am sure are 14 year olds who don't understand the limits of their knowledge. Some are confident readers of trashy news papers or have strong political motivation. The idea though that this is an issue about the editors who protect WP as is as silly as saying that wikiproject medicine is a "troubling conspiracy" of wikipedians who are medically qualified trying to keep wikipedia in line with established medical practice. --BozMo talk 19:52, 24 September 2009 (UTC)

Based on your response, I'm going to venture that a failure on my part to communicate more clearly is a principal culprit. Let me try restating my point:

There's no evil Cabal. There is a group of like-minded editors that support each other. This is usually beneficial to Misplaced Pages. The main harmful activity I see is involved* editors overwhelming content and conduct discussions on noticeboards, especially when involved* editors present their opinions as though they were uninvolved parties and/or generate the false appearance of outside consensus. (*"Involved" defined simply as actually previously or currently involved in content disputes within the topic area that are directly relevant to the discussion or substantial conflict with the main involved parties.) A complete rejection of all concerns about "clique editing" is inappropriate in the face of this very real problem.

I will certainly agree that this is at least as much of a problem with pseudoscience/fringe editors as with skeptical/scientific editors. Indeed, I say it is more of a problem with the former than the latter, if for no other reason than fringe editors' preferred versions are usually inaccurate presentations with far worse NPOV violations and gaming the content noticeboards allows them set policy precedents grossly at odds with the principles invoked.

I hope this better clarifies what I was trying to express (obviously with limited success and much misunderstanding). If I can further clarify, or if you or anyone else wishes to discuss it further, I remain available to do so. Vassyana (talk) 11:54, 25 September 2009 (UTC)

Thanks Bozmo. I've cut my hair recently so we may not be too far opposed on that aspect (unless you now have long hair). As to expanding the page - that will come in time. I'm glad you (V) are watching but I'm afraid I've grown rather discouraged by arbcomms ability to learn, so I won't be in a hurry. That page is mostly for me, though you are free to ask questions there if you like and I'll probbaly answer. In the meantime, on the "fools" issue, User:William_M._Connolley/For_me/On_civility#Misc_arbcomm-y_stuff refers William M. Connolley (talk) 20:11, 24 September 2009 (UTC)

Everyone does at least two foolish things a day, but only some of us can do six impossible things before breakfast. Verbal chat 20:16, 24 September 2009 (UTC)

Second BozMo. A clear description of the situation. My hair is short, my Dr. rer. nat. is from one of the better German universities, and I represent the "no kids" demography. --Stephan Schulz (talk) 09:10, 25 September 2009 (UTC)

Moving on to User:Brews ohare/Speed of light (Example). Take two points A & B. Suppose they are some fixed distance apart. (The actual distance between A & B can be measured, for example, using interferometry to determine the separation in units of wavelengths of some atomic transition). Suppose (hypothetically) measurement skills increase and the transit time of light between points A & B is measured to be a time tAB that is a slightly shorter time than previously measured with older technique. In that case the real speed of light as determined from the relation real speed = (actual distance between A & B)/ tAB will be measured as larger, because points A & B have not changed position, and the time-of-transit tAB has shortened. - this is wrong. OK, at time 1 we measure the distance between A and B as d1, and the time of flight as t1. Later, we measure the distance as d2, and the time of flight as t2. I believe that you are assuming that d1 and d2 are identical in both cases (perhaps d2 is not actually measured) so we can skip here what it means to say that d1 or d2 have been measured. But if t1 != t2, that tells you nothing about the physical speed of light, nor anything about the definition of the metre: it simply tells you that one of the measurements is in error. Why is that interesting? William M. Connolley (talk) 16:30, 16 October 2009 (UTC)

Yes, the assumption is that we know somehow that points A & B are stationary relative to each other. The idea here is not expressed clearly, I guess. The notion is that in era one with technology one we measure t_AB1. Then in era 2 with technology 2 we measure t_AB2. These times differ because of technology differences, which may include greater precision or new corrections not previously considered. The corresponding speeds of light d_AB / t_AB will differ, not because the actual speed of light is different but because we measured it better. The rest of the discussion is a comparison of the roles of this change as seen in SI units where the "speed of light" is always 299 792 458 m/s but the metre changes and a different perspective where the "speed of light" is measured (in some units, say fringe counts/s) and can change. Brews ohare (talk) 16:45, 16 October 2009 (UTC)

I'm still a bit baffled. Why is this a philosophical issue rather than simply a question of measurement error? You don't even need to invoke different eras. *Every* time you do the experiment you will get a slightly different value - so what? You may care to respond to H's comment too: I have been assuming that we all agree that SoL is "really" a constant William M. Connolley (talk) 16:58, 16 October 2009 (UTC)

Perhaps the issue is a non-issue for you. The issue addressed was that "speed of light" in SI units is 299 792 458 m/s, is exact (no measurement error), and never will change. However, in some units the "speed of light" can be measured and its value can change, and it will have an associated measurement error. This distinction in usage of "speed of light" was the cause of much stink and led to the wildly inappropriate behavior now under examination at Case/SoL. Brews ohare (talk) 17:11, 16 October 2009 (UTC)

Misunderstanding of this distinction led to such notions as: the 1983 definition was a response to "improvements in accuracy of measurement of c" (although, in fact, no improvements in this regard took place at this time), and led to a series of debates over renaming the title of the subsection "Definition of the metre". There still are artifacts in the SoL article reflecting a misunderstanding of this distinction. Brews ohare (talk) 17:17, 16 October 2009 (UTC)

Hmm. As I said (but only implicitly), saying that the SoL is 299 792 458 m/s is wrong. It perhaps makes things clearer to say that in the post-1983 world, SoL is 299 792 458 v, the metre is then 1 v*s long. Of course v = m/s and m = v*s; pre-1983 it made sense to think in terms of m, s and m/s. Post-1983 one should think in terms of v, s and v*s. Hence, in SI units SoL is 299 792 458 v, exact, no measurement error, and never will change. Any measurement error is assigned to varying the length m instead (you have somewhat obscured that in your example by insisting that d is constant) William M. Connolley (talk) 17:20, 16 October 2009 (UTC)

I'd say you are on the right track. Yes, pre-1983 one thought in terms of metres and seconds, and speed was m/s. Post-1983, one thinks in terms of times of transit t, and lengths are 299 792 458 m/s × t. Length comparisons are transit-time comparisons:

${\displaystyle {\frac {\ell _{1}}{\ell _{2}}}={\frac {c\ t_{1}}{c\ t_{2}}}={\frac {t_{1}}{t_{2}}}}$

This equation shows that the actual value of c doesn't matter in this approach, and that (as we know) the speed of light can be set arbitrarily by committee decision.

Speeds are not measured absolutely any longer but only as multiples of the speed of light, which is itself unmeasurable in SI Units, being fixed by convention as 299 792 458 m/s. Brews ohare (talk) 17:36, 16 October 2009 (UTC)

Please notice that assuming d_AB is constant does not suggest it is a constant number of metres. It absolutely is not. Brews ohare (talk) 17:25, 16 October 2009 (UTC)

We may be close to agreement. Lets try to clarify this by postulating a universe in which the SoL does indeed slowly vary, let us say to increase, by an amount large enough to clearly measure (let us suppose that in some way we know that this is "physically true"). Pre-1983 we would, using our fixed metres and fixed seconds, measure the SoL increasing. Post 1983, with our fixed SoL and fixed seconds, we would measure our metre shrinking. Yes? William M. Connolley (talk) 20:49, 16 October 2009 (UTC)

Exactly. In fact, this was the first example I attempted some time ago, which was attacked with the query whether GR would allow the SoL to change without some changes in d_AB. So I switched examples. Brews ohare (talk)

(outdent) OK. All of that was then, I think, something of a diversion. Lets go back to your example. We're in the post-1983 world where the metre is defined in terms of SoL and second. You say: If c is used to denote the real physical speed of light (the distance between points divided by the time it takes for a signal to transit them) and c0 = 299 792 458 m/s, the SI-units post-1983 conversion factor (also referred to as the "speed of light" in the SI system of units), then the example shows that logically c ≠ c0, even though numerically c and c0 are nearly the same. I don't accept that (c0 == c; the two are exactly the same, by defn; any "difference" shows up in the metre, not SoL); let us go on: Take two points A & B. Suppose they are some fixed distance apart. (The actual distance between A & B can be measured, for example, using interferometry to determine the separation in units of wavelengths of some atomic transition). But here you have a problem. You cannot use an indepenent defn of distance. You are *obliged* to refer any defn of distance back to the SoL, via distance = flight_time * c0. So if you want your points to be a "fixed distance apart" then this has only one meaning: that the time it takes light to traverse their separation does not vary. If the time taken does vary (really, not because of measurement errors. While I'm here: can you clarify that variation due to measurement errors is not of fundamental interest?) then they are not a fixed distance apart, because that is how you have defined distance. My suspicion is that you are thinking of the case of two marks engraved on a solid bar of steel, or somesuch, such that you "know" they cannot possibly be moving apart; and you are thinking of the case of a slowly-varying "real" change in the SoL; and you are thinking that if the time-of-flight between the marks changes that would demonstrate a "real" change in the SoL. If so, I think you are wrong. Suppose (hypothetically) measurement skills increase and the transit time of light between points A & B is measured to be a time tAB that is a slightly shorter time than previously measured with older technique. - this is just measurement error, and not interesting. If the experimenters, however, insist on using their measurements then the change is to the metre, not to the SoL (to repeat myself) William M. Connolley (talk) 21:59, 16 October 2009 (UTC)

Responses

Wow, that's a lot to go through. It appears that you wish to use the example of varying light speed, rather than the example of improving measurement, because "measurement error is not interesting". Although it may seem that measurement errors are not fundamental, they serve the purpose of illustrating logical differences between the pre and post 1983 definitions. As previously agreed, pre-1983 improved accuracy affects the measured speed of light; post-1983 improvements affect the metre and the speed of light is unchanged, being a defined value. That is the only point that needs to be made, and this example establishes it: the methods are different, and the meaning of "speed of light" in the two cases is different.

A point I don't follow is "c ≡ c₀; the two are exactly the same by definition". Unless c and c₀ both refer to post-1983 SI units, that is a blow to rapport. IMO c₀ is an arbitrary number peculiar to the SI Units (see Jespersen "fixed and arbitrary" and Sydenham), while c is a property of the universe that can be measured in some systems of units (for example, pre-1983 units), but not in today's SI Units.

Have we derailed? Brews ohare (talk) 22:41, 16 October 2009 (UTC)

Yes, it would appear so, I think due to lack of precision in text. Wow, that's a lot to go through. - yes, but I don't think you did. It appears that you wish to use the example of varying light speed, rather than the example of improving measurement - no; in the bit immediately above, I was forced to assume "constant" light speed because your example can't be made to work with "variable" light speed because you insist the points are the "same" distance apart. I'll respond again, but I'd like you to answer two points in particular - I've gone back and marked them with and William M. Connolley (talk) 07:23, 17 October 2009 (UTC)

Can you clarify that variation due to measurement errors is not of fundamental interest?

This is a confusing question because I have indicated that it is of fundamental interest in two ways: it provoked the 1983 decision and my example uses measurement error to illustrate the two different roles of 299 792 458 m/s. Brews ohare (talk) 15:15, 17 October 2009 (UTC)

What provoked the 1983 decision is not of fundamental interest at this point. As to the second point, I'm not getting through on that so will give up there William M. Connolley (talk) 20:47, 18 October 2009 (UTC)

+ My suspicion is that you are thinking of the case of two marks engraved on a solid bar of steel, or somesuch, such that you "know" they cannot possibly be moving apart.

This is an observation, not a question. Yes, the assumption is that the two points are not separating. The logic of the matter does not require a proposal for establishing this fact, although that would be nice. Your view is that any means of establishing they don't move begs the question. If that is really necessary to the argument (I regard it as prettying it up, inasmuch as there is clear evidence that the pre- and post- 1983 approaches are different) it probably would take the form of examining the separation in wavelengths and comparing it with the separation in time-of-transit. Assuming sufficient precision that the two methods are comparable, if the two lengths are the same on one occasion and differ on another, then c itself (the one in relativity) changed.(Or, maybe the universe expanded, leading to red shift: we're going to get involved in estimating the reasonable extent of various causes and the validity of murky theories). However, c₀ (the one in the SI units) is impervious to change, except by committee decision. (If the real speed of light changes enough that the altered metre intrudes on the world economy, they'll change c₀.) Evidently c & c₀ are linked by committee thought processes, but c ≢ c₀. I don't feel the need to go into such thought experiments in order to make the point here. Brews ohare (talk) 15:15, 17 October 2009 (UTC)

OK, this I think is your fundamental problem. Once we have one definition of distance, the metre, which post-1983 is based on SoL, then you are not allowed to have another one, unless they are equivalent. If your definition of distance is based on SoL, and if you measure different times of flight between two fixed marks in different experiments, then you can (1) put this down to measurement error and ignore it, or (2) decide that it is too big for measurement error and thus you are obliged to say that the marks have moved further apart (or you could (3) decide to throw out your definition and get another I suppose). But until you do (3) you cannot go an pick some other measurement standard like counting wavelengths. This is why your example is broken. Once you have said that the SoL is fixed then any alteration in measured times-of-flight translate into changes of distance, not into variations of SoL, because it cannot vary by definition. You say the assumption is that the two points are not separating - but it is vital to realize that this statement is meaningless without an agreed way of deciding if the two points are separating or not. We do have an agreed way of deciding: we measure the distance between them. And we have an agreed way of measuring the distance: we measure the flight time of light. Doing anything else is doing something other than measuring their distance William M. Connolley (talk) 20:47, 18 October 2009 (UTC)

I'm uncertain whether I'm free to answer your comments in view of the ban in progress. I think it hasn't quite closed yet, though the votes are in. Here is a point of confusion: I wish to consider two different approaches to measuring a length: one is wavelength based and one is transit-time based. Sometimes I may be confusing because I use the pre-1983 metre as an example of the former and the post-1983 metre as the latter. I do not intend that both are legally in force at the same time: they just represent different methodology. Thus, put the metre aside for the moment. I am free to measure the separation of points A & B in wavelengths or in transit times at time t₁ and again at time t₂. If, for example, the two wavelength measurements agree and the two times-of-transit disagree, I have to come up with an explanation, for example, the speed of light c (the one in relativity) changed. Other explanations are possible. However, of course, regardless of the explanation finally adopted, regardless of whether c is determined to have changed, c₀ has not changed. Brews ohare (talk) 00:22, 19 October 2009 (UTC)

I posted this comment following your exchange with Physchim62, and as you can see, such discussion is not possible. Brews ohare (talk) 17:31, 19 October 2009 (UTC)

To be clear, BO, are you stating that the speed of light is not a constant using old meters?Hipocrite (talk) 17:38, 16 October 2009 (UTC)

I'm butting in with my answer to this question. Please indulge me: In old metres, whether the speed of light is constant was an experimental question, although it appeared to be constant to within measurement accuracy. Post-1983, this question becomes an experimental question only if one identifies a length other than the metre so that speeds can be measured. For example, one could take some wavelength as unit and measure the speed of light in wavelengths/s. Brews ohare (talk) 17:58, 16 October 2009 (UTC)

Its an easy question. Please don't be elusive ("appeared to be constant to within measurement accuracy") - are you stating that the speed of light is not a constant using old meters? Thanks! Hipocrite (talk) 18:01, 16 October 2009 (UTC)

I thought my answer was clear: we don't know. More carefully, it is constant so far as measurement can determine at this time. Still more carefully, it is 299 792 458 ± 1.2 m/s in old metres. Brews ohare (talk) 18:06, 16 October 2009 (UTC)

So, in summary, you recognize that the new meter measured in old meters is exactly 1 meter, right? Hipocrite (talk) 20:03, 16 October 2009 (UTC)

I have a feeling that things are getting more subtle than needed. However, I think my answer is "no". I'll try putting my answer together as follows: first, from a logical standpoint they are very different: The old metre was a fixed number of wavelengths; the new meter is the distance that light travels in the standard time interval. Second, from a standards standpoint, the standard time interval is arbitrary, but was chosen to result in a new metre pretty close to the old metre. I'd say to within experimental accuracy they were the same length, but refinements in measurement might show they are different to a tiny degree. Would you find this argument acceptable? Brews ohare (talk) 20:34, 16 October 2009 (UTC)

(undent) It's becoming very hard to determine if you are challenging the accuracy of special relativity. Are you? You are aware, of course, that your compatriot in this is, in fact, challenging the accuracy of special relativity, which is why it's very important for him to make the article on the speed of light of as little use to individuals who want to understand what the massive overwhelming super-duper-ultra-majority of scientific opinion speed of light is as is humanly possible. You are aware that this is the objective of your partner, right? Hipocrite (talk) 20:40, 16 October 2009 (UTC)

I've said below that I have no interest in challenging the special theory of relativity. I also do not view D Tombe as my "partner". I do appreciate his support on the Speed of light issue, where I have found him to state the case quite eloquently on several occasions. I do not see that anything that has been written about the 1983 decision in the article Speed of light has reduced the article's utility. In fact, I'd argue that the present lead (because of its greater explanation for why an "exact" "speed of light" is feasible) is an improvement over Martin Hogbin's lead, which made an exact speed of light sound like the tenth wonder of the world, and was a clear violation of WP:Astonish. I think you misjudge D Tombe in thinking he wishes to undermine the utility of this or any other article on WP. He has his views and wishes to see some openness of mind. That is different. Brews ohare (talk) 20:54, 16 October 2009 (UTC)

Comment: I believe that it would be helpful to answer this. Do you believe that SR is essentially correct ("essentially" covers "as amended in the real world by GR" etc). For reference, I do William M. Connolley (talk) 20:51, 16 October 2009 (UTC)

Yes, I do. I am aware that there are some questions about it on a Planck scale, but that they are open questions at the moment, and will not greatly impact its present application, in much the same way that SR has not unseated classical mechanics. Brews ohare (talk) 20:58, 16 October 2009 (UTC)

Sorry, I didn't catch that I was BO. No, I do understand that the metre changes. Please take a look at this & this. I agree with your remarks. Brews ohare (talk) 19:51, 16 October 2009 (UTC)

I've looked at the intro of User:Brews ohare/Speed of light (1983 definition). I can agree with all of it, with the exception of The effect of this definition is to redefine the term speed of light in vacuum as a conversion factor with the exact value 299,792,458 m/s. The role of the SoL post-1983 is exactly analoguous to the role of the metre pre-1983, and I can't see anyone calling the metre a "conversion factor". Do you insist on this point? If so you'll need to explain it further William M. Connolley (talk) 20:58, 16 October 2009 (UTC)

I don't know that I insist upon it. (BTW, it is c that is the conversion factor, not the metre.) It is the term used by the cited reference: "One fallout of the new definition was that the speed of light was no longer a measured quantity … defining one unit in terms of another removes a constant of nature by turning c into a conversion factor whose value is fixed and arbitrary." (Emphasis mine). It seemed at the time to provide a useful description to distinguish 299,792,458 m/s in the SI Units from the measured 299,792,458 ± 1.2 m/s. Brews ohare (talk) 21:25, 16 October 2009 (UTC)

OK, that is a book, but clearly a non-weighty tome: I hope you're not going to insist it can be utterly relied on. "c" can be considered a conversion factor post-1983, *but only in the sense that the metre was a conversion factor pre-1983*. Do you agree? It is in this sense that I find calling c a conversion factor odd, because pre-1983 it would have sounded very odd to call the metre a conversion factor William M. Connolley (talk) 21:32, 16 October 2009 (UTC)

The source was written by some folks at NIST, I believe, so though a popular treatment, still authoritative. A "weighty tome" is Sydenham, who says: "the time standard will serve as the length standard provided suitable apparatus exists to make the conversion from time to length via the constant c." (Emphasis mine.) Another one is Taylor and Wheeler who ask: "fundamental constant of nature"? Or a mere factor of conversion between two units of measurement". (Emphasis mine.) However, as already said, the purpose here is not to misapply some technical term but to label a distinction between the use of a defined SoL 299,792,458 m/s along with a transit time from a measured SoL of 299,792,458 ± 1.2 m/s based upon a metre in wavelengths. A different way to do this is to use the number itself, as done here. Brews ohare (talk) 21:47, 16 October 2009 (UTC)

If you appreciate that the post-1983 definition of the metre allows for variation then I am confused as to why you don't recognise that the valuse 299,792,458 m/s is the speed of light (in the physical sense). You note that, in pre-1983 metres, it was known that the speed of light is 299,792,458 ± 1.2 m/s, with a stated uncertainty of 1.2 m/s. In post-1983 metres, the value of the c is fixed but the uncertainty remains, it is just that it is in the unit rather than the value. Consequently the pre-1983 299,792,458 ± 1.2 m/s and the post-1983 299,792,458 m/s are identical because the uncertainty has simply been moved from the value to the length of the metre (and hence, to the unit). This may seem an unusual arrangement but it does not create some new speed of light that is unrelated to the physical phenomenon of light propagation. EdChem (talk) 04:31, 17 October 2009 (UTC)

I understand all that very well. I still think there is something to say. Brews ohare (talk) 14:55, 17 October 2009 (UTC)

(outdent) Brews, I'd like you to answer the question I've asked several times: do you understand that SoL is a "conversion factor" in the new system in exactly the same way that the metre is a "conversion factor" in the old system? William M. Connolley (talk) 07:27, 17 October 2009 (UTC)

No, I don't. You can explain that to me, and also please explain why that has any bearing on the implications of the 1983 decision. If the question is the utility of the term "conversion factor", change the labeling. If the issue is that dx = c dt converts time to distance in relativity, IMO that greatly predates the invention of the number c₀ with the 1983 definition. Brews ohare (talk) 14:53, 17 October 2009 (UTC)

Ah excellent (in a sense): we have something clear and specific on which we disagree, rather than the rather vague stuff. I'll clarify what I mean in a bit. In the meantime, I've just read and disagree with it; this is related to the same point. You write Setting the speed of light to a defined numerical value in the SI units means comparisons of length become equivalent to comparisons of transit times of light - but this is a problem. If (post-1983) comparisons of length are *equivalent* to transit times, then (obviously) comparisons of transit times are equivalent to comparisons of length, since "equivalent" is reflexive. But that is exactly the same as the situation per-1983. So "become" is wrong. Do you really mean to use the word "equivalent"? Were you to mean "are done by" my objection would not be allowed in that form William M. Connolley (talk) 18:10, 17 October 2009 (UTC)

Hi William: Our little tête à tête is likely to be cut short by a ban on my entering such conversations. However, we'll see how far it can go. I follow the reflexive notion, which I'd say is expressed equally by:

${\displaystyle {\frac {\ell _{1}}{\ell _{2}}}={\frac {c\ t_{1}}{c\ t_{2}}}={\frac {t_{1}}{t_{2}}}}$

Post 1983 ℓ = c₀ t. Pre-1983, ℓ = c t, and as the value of c divides out of the ratio it doesn't matter, transit times could have been used all along. But they were not, eh? Ratios of fringe counts were compared. I expect you agree with all this: maybe my wording is poor. Brews ohare (talk) 21:27, 17 October 2009 (UTC)

Ah well, such is life. Point me at the decision and I'll ask for an exception for people who have specifically invited discussion. On the "reflexive" issue, I don't think you've understood what I mean by it. I mean: if a is equivalent to b, then b is equivalent to a. So your text above is exactly equal to Setting the speed of light to a defined numerical value in the SI units means comparisons of transit times of light become equivalent to comparisons of length. Which is just as true pre-1983. So "becomes" is wrong, which I said before William M. Connolley (talk) 23:03, 17 October 2009 (UTC)

William: There is no need to go into semantics here. I thought I had agreed that it was equally possible to use transit times pre-1983, it "was just as true pre-1983". It just wasn't how it was agreed upon to do it. I am not married to my wording. Maybe you'd like a different wording: go ahead and propose one. Here's a possible: Setting the speed of light to a defined numerical value c₀ in the SI units means comparisons of transit times of light become equivalent to comparisons of length because lengths are determined as proportional to transit times: ℓ = c₀ t. That is different from the pre-1983 approach where lengths were determined directly in terms of wavelengths (as fringe counts). As Sydenham says, post-1983: "the time standard will serve as the length standard". Brews ohare (talk) 14:47, 19 October 2009 (UTC)

I think I misunderstood what you meant by "becomes"; I had thought you mean "changes in time as we pass over 1983" but now I think you mean "when you write it in this way". OK, we can dispose of the "becomes" point as being uninteresting William M. Connolley (talk) 20:53, 19 October 2009 (UTC)

Let me see if I can summarize the situation briefly. The mainstream view is that the speed of light is a physical constant, in the sense that irrespective of our relative velocity to the source, we will always measure the exact same value. The fact that this approach is in total contradiction to the principles of Galilean relativity is the very cornerstone of Einstein's special theory of relativity. This issue has got absolutely nothing to do with the constancy of the speed of light that arises in connection with modern SI units.

The argument at the 'speed of light' article has not been over the issue of agreement or disagreement with the special theory of relativity. The argument has been over the issue of the need to clarify the fact that when the speed of light is expressed in SI units (post 1983) it is a fixed number that is beyond measurement, and that it is a tautology which is conceptually different from the physical speed of light. In modern SI units, the physical reality of the speed of light has been shifted into the metre itself. Once we then express the speed of light in terms of that metre, the physical reality gets canceled out, and we end up with our original chosen number thrown back at us.

My assessment of the dispute at 'speed of light' is that Brews ohare brought this truth to the attention of a group who had never previously thought the matter through fully. He then came up against the standard human resistance that arises in such a situation. As the battle raged on, most editors came to understand the issue fully, but there were issues of pride and principle that made them refuse to embrace Brews's viewpoint that the matter really needs to be fully clarified early on in the article.

Let's now move on to the issues of opinion. It shouldn't really matter what one's opinions are about special relativity. However, I am of the opinion that ardent supporters of special relativity will have a vested interest in clouding the distinction between the two concepts, and this may also be part of the reason behind the enormous resistance that Brews has encountered, even if Brews himself actually supports relativity.

There are however an enormous number of scientists who disagree with special relativity and that the speed of light is constant as described above. It is therefore a convenience for the mainstream relativists to have the constancy of the speed of light additionally enshrined into the system of units as a means of consolidating the theory of relativity. That was not the ostensible purpose of BIPM's decision in 1983, but I strongly suspect that it was indeed an underlying motive.

My own problem with the BIPM decision, is the knock-on effect which it has for electric permittivity. David Tombe (talk) 01:37, 17 October 2009 (UTC)

I got as far as when the speed of light is expressed in SI units (post 1983) it is a fixed number that is beyond measurement, and that it is a tautology which is conceptually different from the physical speed of light. before disagreeing. It isn't a tautology (before you insist that it is, please read this). The SoL (post 1983) is different from the "true physical" SoL in exactly the same way that the metre, pre-1983, was different from the "true physical" metre. Do you agree? William M. Connolley (talk) 07:33, 17 October 2009 (UTC)

William, You've made the same point that David J Wilson made, which is that Colonel Warden's source is specifically referring to the 'constancy of the speed of light in SI units' as being a tautology, and not to the speed of light itself. There is truth in what you both say. But the SI speed of light itself is a fixed number, which is merely the number that was chosen for the definition of the metre in terms of the speed of light. When we then express the speed of light in terms of that metre, the physical reality gets cancelled out, and the number gets thrown back at us. So irrespective of what Colonel Warden's source actually means, the SI speed of light itself is also a tautology. It's possible that Colonel Warden's source might be referring specifically to the 'constancy of the SI speed of light' as being a tautology, in the sense that it is constant because it is a fixed number by definition. That would then be a tautology within a tautology. In that case, the primary tautology would be the fact of the SI speed of light being akin to saying that light travels at one light-year per year. Colonel Warden's source stated this latter point too. So it's a question of what Colonel Warden was referring to when he said that it was a tautology. The grammar does rather tend to say that he was referring to 'the constancy of the speed of light'. But the wider context would suggest that he was referring to the whole package as being a tautology. The 'constancy of the speed of light in SI units' and the fact that the speed of light in SI units is a fixed constant, all blend into the same thing in my opinion. And the whole package is either a tautology, or a double-decker tautology.

As regards your specific question, the metre, both pre-1983 and post-1983, was and is the same thing as the true physical metre. In my opinion, length and time are fundamental dimensions. Speed, which is length/time, is a compound concept. Once we start playing games and reversing the situation as regards what is fundamental, we end up with the confusion that we have been witnessing here for months. And it all backfires right into the plate of electric permittivity. David Tombe (talk) 13:15, 17 October 2009 (UTC)

OK, I think we have agreement that the source is talking about "constancy of the speed of light in SI units" as being a tautology, and not to the speed of light itself. That means you have no good source for the SI speed of light itself is also a tautology, as you recognise. Clearly it is your presonal opinion that it is a tuatology; I disagree. But presumably you realise that, having no source for this contentious point, you cannot put it into an article?

As regards your specific question - but alas you have not answered it. I've marked it with above for clarity. You need to answer clearly "yes" or "no" and then, if you desire, explain why William M. Connolley (talk) 14:41, 17 October 2009 (UTC)

William, First we need to clarify another point here. I have not been heavily involved in addressing this issue in the main article, and I don't recall ever actually intending to explicitly state in the main article that the SI speed of light is a tautology. My main contribution to the 'speed of light' article was in the history section. On the talk page, I argued from natural reasoning that the SI speed of light is a tautology prior to even seeing any sources, and a number of people have agreed with me. The purpose of that talk page argument was to highlight the need to clarify the distinction between the SI speed of light and the real speed of light in the main article. Sources were provided which stated that distinction.

But having said that, I do not agree with your cut and dried analysis above of Colonel Warden's source. I haven't got the quote handy, but from memory, he begins by drawing attention to the fact that the SI speed of light uses a metre that is defined in terms of the speed of light. He then points out that this means that the SI speed of light is a fixed constant, akin to saying that the speed of light is one light-year per year. At this point in the quote, Colonel Warden's source has clearly drawn attention to a tautology, even if he hasn't explicitly said so. The idea of the speed of light being one light-year per year, is a classic example of a tautology. Then Colonel Warden continues something along the lines that no experiment is now needed to show the 'constancy of the speed of light' because it is a tautology.

It is not at all clear here that he is specifically referring to the 'constancy of the speed of light'. The source doesn't explain in what respect the constancy is a tautology, although I can see how it is. The 'constancy of the speed of light' is a tautology because the SI speed of light is a constant by definition. There is every reason to believe that when the source uses the word tautology, that is is referring to the whole package in the quote.

There is clearly a double-decker tautology in all of this. The source draws specific attention to the lower deck of the tautology as regards the analogy that the speed of light in SI units is the same as saying that the speed of light is one light-year per year. But when the source then explicitly uses the word tautology, it might appear from the wording to be directed only at the upper deck of the same tautology. But the overall context would tend to oppose that narrow literal interpretation. So I don't agree with you that the source is unequivocally only referring to the upper deck of the tautology. I would classify your counter argument as being a play on words. You must surely only be acting as devil's advocate here, are you not?

On your other question, I have to answer 'no', for the reason that I don't agree with your analogy. The conceptual split as between the SI speed of light and the real speed of light has never been paralleled in the more fundamental parameter of length. A metre has always been the same thing as the physical metre. David Tombe (talk) 02:47, 18 October 2009 (UTC)

I don't recall ever actually intending to explicitly state in the main article that the SI speed of light is a tautology - I raised the point because it appeared prominently in the Arbcomm pages. I assume that means for you that it was an important point. If it isn't, then it would appear to be a tactical error on your part to speak so much about it.

In my opinion, length and time are fundamental dimensions. Speed, which is length/time, is a compound concept - I'm sure this is a defensible concept. I'm not sure it is correct, or indeed even meaningful.

There is clearly a double-decker tautology in all of this - no, this isn't clear at all. Indeed, we disagree on this. I hope this is just an error in your wording - you mean "It is clear to me (DT)" - you don't mean "And obviously any well-informed person will agree".

I would classify your counter argument as being a play on words. You must surely only be acting as devil's advocate here, are you not? - no.

On your other question, I have to answer 'no', for the reason that I don't agree with your analogy. - it isn't an analogy. Please consider carefully whether you think it is or not.

The conceptual split as between the SI speed of light and the real speed of light has never been paralleled in the more fundamental parameter of length. A metre has always been the same thing as the physical metre. - this is completely wrong. I do not need any more answers from you to now have a firm opinion of your grasp of the physics.

William M. Connolley (talk) 08:16, 18 October 2009 (UTC)

William, The source clearly points out that the SI 'speed of light' is equivalent to saying that the 'speed of light' is one light-year per year. One light-year per year IS a tautology. And you are seriously trying to say that it is not the tautology that the source is referring to?

The source - I'd like an exact quote for what you're quoting here. The 1983 defn of the metre is not a tautology, as I've said before . CW's source doesn't say so, ditto. I disagree with your *opinion* that it is a tautology. If you wish to press this point, you'll need to find a logical argument so far lacking, or an authoratitive and unambiguous source stating it William M. Connolley (talk) 20:36, 18 October 2009 (UTC)

As for your last point, you are the first person that I have ever heard suggesting that the metre is different from the physical metre. That kind of conceptual distinction has never been raised before to the best of my knowledge. You need to convince me that you understand the physics by explaining the difference to me. David Tombe (talk) 12:34, 18 October 2009 (UTC)

I'm not particularly interested in convincing you that I understand physics, and don't intend to try. What is very badly wrong with your statement that I objected to is your assertion that length is more fundamental than speed William M. Connolley (talk) 20:36, 18 October 2009 (UTC)

Referring to the above comment of David Tombe, "Speed, which is length/time, is a compound concept.":

As I read a book by N. David Mermin , it seems to permit the following viewpoint (the last chapter or so are not so happy, but I am talking about the main thread of the book). Mermin shows how to compare velocities, including comparisons with the velocity of light, without having defined units of distance and time; one needs for this repetition of arbitrary measuring rods in an inertial observation frame, and lights; these are fundamentally important and essential mechanical presuppositions but are not quite realizations of units of space and time. The following is assuming that things are investigated in a laboratory that is located so far from any external massive object that gravity is near enough to zero. The reason for this assumption is to exclude from this present discussion the problems of the effect of gravity on the speed of light, on the length of a measuring rod, and on the rate of natural processes, such as internal atomic dynamics that set the rate of clocks. The main presently relevant idea under this assumption is that the propagation of light is a most fundamental fact of nature. It is more fundamental than space and time, which are derivative concepts that may differ, and indeed do differ, from observation frame to observation frame, and therefore differ for observers who are living in observation frames which move relative to one another. A large store of patience is needed to follow up the works of Alfred Arthur Robb (starting with Robb, Alfred (1911). Optical geometry of motion, a new view of the theory of relativity. Cambridge: Heffner & Sons.) Robb seems to me to show, by a very rigorous argument that he sets out in exhaustive detail, that it is logically valid to start with the propagation of light as the most fundamental notion, and to derive from it the notions of space and time. Perhaps needless to say, Mermin does not mention Robb. A central concept here is that of the inertial observation frame, that is to say an observation frame that is not subject to any external force, such as gravity or the motor power of a rocket engine; this can be realized only to a degree of approximation, and never logically perfectly; one has to get far enough away from any external gravitational influence for one's purposes (see for example ). Robb's last book (Robb, Alfred (1936). Geometry Of Time And Space. Cambridge: University Press.) has in its index four references to Einstein, one reference to Larmor, two references to Lobatschewski, two references to Lorentz, seven references to Minkowski, and no references to Poincaré. My own view is that the propagation of light is an example, nearly our only practically accessible example, of a more general and more fundamental fact of nature, the propagation of causal agency. I regard the latter as the most fundamental concept of physics, and necessary to make sense of the concept of empirical or experimental science.Chjoaygame (talk) 21:47, 17 October 2009 (UTC)

I agree William M. Connolley (talk) 08:16, 18 October 2009 (UTC)

EdChem, You said above,

I am confused as to why you don't recognise that the value 299,792,458 m/s is the speed of light (in the physical sense) (EdChem)

You are of course referring to the post-1983 SI units speed of light.

The answer is that it's because it expands to read 299,792,458 times the distance that light travels in 1/299,792,458 seconds, per second. It tells us no more physical information than saying that the speed of light is one light-year per year. Or imagine another scenario. A professor tells his students that the speed of light is 1. One student puts up his hand and asks 'Sir! What system of units are we using when the speed of light is 1?'. The professor replies, 'we are using the system of units in which the speed of light is defined as 1'. Would the students be any wiser about the speed of light?

What you seem to have failed to notice is that when we express a speed in terms of a distance that is already defined in terms of that speed, the physical significance gets canceled out, and we get our chosen fixed number thrown back at us, and it is a totally useless piece of information. What has deceived you is the fact that you can already relate to the magnitude of the metre, because the chosen number was deliberately so chosen to make the new post-1983 metre more or less the same size as the pre-1983 metre. In other words, you have inside knowledge which deceives you into thinking that 299,792,458 m/s is actually telling you something. David Tombe (talk) 13:32, 18 October 2009 (UTC)

Let's then also re-open a debate about the conversion of the Calorie to the Joule. The Professor tells to student that if you measure heat in the same units as work (e.g. both in terms of Joules), you get:

dU = dQ - dW

Otherwise, you'll have to write:

dU = c dQ - dW Count Iblis (talk) 14:26, 18 October 2009 (UTC)

The answer is that it's because it expands to read 299,792,458 times the distance that light travels in 1/299,792,458 seconds, per second - no. It expands to 299,792458 v. You are still caught up in your idea of the absolute primacy of the unit of distance, which for you is somehow "obviously" more basic than that of speed. I think this is your fundamental problem. when we express a speed in terms of a distance that is already defined in terms of that speed is a misreading of the definition. This is any easy mistake to make, because people carelessly write, and more carelessly think, that SoL = 3e6 m/s; when it is really that SoL = 3e6 v, and then 1 m = 3e6 v * 1s / 3e6 William M. Connolley (talk) 20:22, 18 October 2009 (UTC)

William, the reply which I gave to EdChem is my final statement on the matter. I cannot make any sense out of your replies. When you state above "It expands to 299,792458 v", I really don't know what you are talking about. You seem to be boldly stating that the confusion lies with myself and Brews. That's not the way I see it. I see it that the confusion lies entirely with yourself. So I can't see any point in continuing this discussion. David Tombe (talk) 02:28, 19 October 2009 (UTC)