Talk:International System of Units/Archives/08/2022

Is "speed of light" misleading?

Please see Wikipedia:Village pump (miscellaneous)/Archive 71#Is "speed of light" misleading? Jc3s5h (talk) 18:41, 26 July 2022 (UTC)

The issue is listing the speed of light as a constant, when it is not a constant. Whether c stands for celeritas or causality is not really the issue here. This is confusing to people studying optics, which relies on the existence of refraction, a phenomenon that relies on the fact that the speed of light is not a constant. The table should include "in a vacuum" at the very least, as the paragraph talking about it does, to avoid this confusion.

The speed of causality, also known as the fastest speed that any one point in the universe can communicate any data to any other point in the universe that is separated in space, is far more specific, and could lead people to reading further on the topic rather than being misinformed.

https://en.wikipedia.org/wiki/Speed_of_light#Upper_limit_on_speeds is a better part of the article to link to in this regard, and is what a link for "speed of causality" automatically corrects/scrolls to. Marrew (talk) 00:30, 27 July 2022 (UTC)

Please stop this disruption. No one studying optics (or anything else) is 'confused' by this terminology. The term "speed of light" universally refers to the speed of light in vacuum. When the speed in a medium is meant, it's always clarified as the speed of light in a medium, such a glass/water/oil/etc... Headbomb {t · c · p · b} 00:54, 27 July 2022 (UTC)

"The term "speed of light" universally refers to the speed of light in vacuum." I simply disagree with this. A thing that changes depending on some other thing is categorically not a constant. Marrew (talk) 00:57, 27 July 2022 (UTC)

The meaning, adopted by convention for many decades, is clear. There is no need for this thread to continue. Xxanthippe (talk) 01:02, 27 July 2022 (UTC).

Just because many people are accustomed to using the wrong term, does not mean we cannot strive to improve articles with better, more specific, language. Marrew (talk) 01:09, 27 July 2022 (UTC)

Wikipedia does not engage in WP:original research or WP:original synthesis and is not a forum for original thought. I think that continued discussion of this matter amounts to trolling. If you continue in this vein you could have your editing privileges restricted. Xxanthippe (talk) 01:20, 27 July 2022 (UTC).

I was told to discuss this here on the talk page, now you are saying that doing so is trolling...can't have it both ways. If this is not the appropriate place to discuss this, where is?

Adding some context so that something is not misleading is not synthesis nor research. Insisting "the speed of light" is the same thing as saying "the speed of light in a vacuum" is making an assumption about what the reader already knows, besides the fact that it is erroneously listed as a constant. Marrew (talk) 01:46, 27 July 2022 (UTC)

Let me add to the overwhelming majority here that agrees that there is no confusion. "Speed of light" without other indication is universally understood to refer to the speed of light in a vacuum. Wikipedia must follow conventional usage until that usage changes, because that is the entire point of Wikipedia - it FOLLOWS secondary sources, it does not LEAD them. PianoDan (talk) 01:56, 27 July 2022 (UTC)

Indeed. The text of the article is already clear on the "in vacuum" point. We don't need to squeeze pedantic qualifications into the table. (Should the row about the cesium hyperfine transition specify the absence of a magnetic field? etc.). XOR'easter (talk) 15:24, 27 July 2022 (UTC)

Concur with the above, in particular with the response to "people studying optics". In fairness to the OP, I think this is a perfectly reasonable question to ask, but the answer is "no" (we're not going to change anything). Primefac (talk) 11:00, 28 July 2022 (UTC)

If the consensus here is that the qualifier "in a vacuum" is unnecessary, because it is always implied when stating 'the speed of light' why does it need to also be included in the paragraph? Why not make it be consistent between the paragraph and the table? Marrew (talk) 15:36, 29 July 2022 (UTC)

Because space is at a premium in a table, but not in the body of the article. PianoDan (talk) 15:55, 29 July 2022 (UTC)

So consistency is unimportant then? Marrew (talk) 16:05, 29 July 2022 (UTC)

Either it needs to be stated every time, or it does not need to be. It can't be both. Marrew (talk) 16:10, 29 July 2022 (UTC)

Interpreting "it does not need to be" as "it must not be stated at all", I don't think that this argument has merit. It is pretty standard to introduce a term in a detailed form to disambiguate it, and then to use an abbreviated form of it further into an article or paper for brevity when there is little room for confusion. A shortened form of something is not inconsistent in the same way as switching between styles, notations, terminology, etc. might be. Taken literally, such an argument would mean that words such as "it", "the", and so on would be disallowed in WP as being inconsistent with the original term. 172.82.46.195 (talk) 17:45, 29 July 2022 (UTC)

It absolutely CAN be both, if that's what the consensus of editors determines is the best approach. Blanket statements like "it CAN'T be this way" are a fundamental misunderstanding of how Wikipedia works. PianoDan (talk) 18:20, 29 July 2022 (UTC)

None of these responses addresses the fact that the speed of light is literally not a constant, and yet is listed without this context in a table of defining constants. Marrew (talk) 03:21, 2 August 2022 (UTC)

That's because you insist on reading the speed of light as meaning the speed of light in media. This reading is idiosyncratic. Headbomb {t · c · p · b} 03:35, 2 August 2022 (UTC)

No, I'm reading the speed of light as what it is, which is NOT a constant. Listing something that is not a thing, with a group of those things, is misleading at best. Your lack of ability to understand or acknowledge this is not a reflection on me or my reading. But again, thank you for the assumptions. Marrew (talk) 16:43, 2 August 2022 (UTC)

Writing the 'speed of light' when you mean 'the speed of light in a vacuum' is the idiosyncratic problem here. This is simply not how words work. Specificity is important, and if Headbomb and Yamla are unable to understand that, I do not know how they obtained alleged P.h.D's... Marrew (talk) 00:55, 8 August 2022 (UTC)

"Because space is at a premium in a table, but not in the body of the article. "

-This argument is invalid as there are other entries in the very same table that are longer, and also require two lines. Adding three words for clarity (which is still less text than other items in the same column) does not constitute a waste of space.

Posting again here to give ample opportunity to for those who initially raised these concerns to respond. Marrew (talk) 02:01, 12 August 2022 (UTC)

No one studying optics (or anything else) is 'confused' by this terminology. The term "speed of light" universally refers to the speed of light in vacuum. When the speed in a medium is meant, it's always clarified as the speed of light in a medium, such a glass/water/oil/etc...

This is an assumption of the reader's familiarity with the content and the english language. This is NOT a universality. Insisting it is because "that is what you have always used" to does not make it less misleading to people unfamiliar with this topic. Furthermore, the need to include the extra context isn't even the contested issue here, as it is used in the article, showing the need for it. Again, consistency and precision are important.

Posting again here to give ample opportunity to for those who initially raised these concerns to respond. Marrew (talk) 02:00, 12 August 2022 (UTC)

I suggest the title of this table be changed from "SI defining constants" to "SI defining concepts"

If you have a problem with this change, maybe ask yourself why you are not arguing for the addition of the words "in a vacuum" to the "speed of light" entry, which as it stands is an erroneous entry of something that IS NOT a constant in a list of alleged constants. Marrew (talk) 18:00, 11 August 2022 (UTC)

The speed of light is always c. The average speed in a dielectric medium may be less because the path is more indirect and so longer, the light being scattered from atom to atom. A treatment can be found in any optics text written after 1950. Of course, a proper treatment involves the full panoply of photon-atom quantum mechanics, but the explanation above should be enough for someone whose knowledge of physics is rudimentary. Xxanthippe (talk) 23:03, 29 July 2022 (UTC).

I still fail to see any valid reason to not include "in a vacuum" in the table.

To address specific criticisms:

"The term "speed of light" universally refers to the speed of light in vacuum."

-This is an assumption of the reader's familiarity with the content and the english language. This is NOT a universality. Insisting it is because "that is what you have always used" to does not make it less misleading to people unfamiliar with this topic.

"space is at a premium in a table, but not in the body of the article."

-This argument is invalid as there are other entries in the very same table that are longer, and also require two lines. Adding three words for clarity (which is still less text than other items in the same column) does not constitute a waste of space.

"Wikipedia must follow conventional usage until that usage changes, because that is the entire point of Wikipedia - it FOLLOWS secondary sources, it does not LEAD them."

"Wikipedia does not engage in WP:original research or WP:original synthesis and is not a forum for original thought."

-Both of these arguments do not hold water as the convention is broken in the paragraph, creating an inconsistency on the page.

The main issue here is the fact that the speed of light is *not a constant*, but is listed in a *table of constants*. Adding the context of "in a vacuum" makes it clear and removes the misleading nature of putting something that isn't a constant in a list of constants.

Until someone can put together a reasonable explanation for why "in a vacuum" makes sense in the paragraph, but not the table (that does not just re-hash the invalid arguments presented here), I am not convinced there is consensus on this issue. Marrew (talk) 22:24, 6 August 2022 (UTC)

You consider the arguments invalid. We do not. Accept consensus and move on, otherwise you won't find this is a very productive use of your time. Headbomb {t · c · p · b} 02:18, 12 August 2022 (UTC)

This discussion is going nowhere. It is time for this thread to be closed. Xxanthippe (talk) 03:20, 12 August 2022 (UTC).

The reason it is going no-where is the failure by anyone to provide good reasoning as to why extra context is warranted in the paragraph body but not the table; especially when the entry is is in conflict with the title of the table (again; the speed of light is not a constant). Marrew (talk) 16:33, 12 August 2022 (UTC)

If this is consensus, why is there still an inconsistency between the table and the paragraph? Marrew (talk) 16:19, 12 August 2022 (UTC)

Also, again Headbomb, try actually answering the merits of the issues I'm discussing. The speed of light is not, and never has been a constant. Insisting that some small set of words always means some other larger set of words is just not how words work. Specificity is important. Not making assumptions about the reader's level of familiarity with a subject should also be a priority. Why are you arguing for making the table more confusing? Marrew (talk) 16:28, 12 August 2022 (UTC)

Marrew's arguments do not convince me, and his argumentative style is tendentious. "Speed of light" when not otherwise qualified is the speed in a vacuum, and is a constant. --Srleffler (talk) 15:12, 14 August 2022 (UTC)

I've attempted to professionally state my reasoning; while being called a troll, obtuse, and now argumentative all by alleged community leaders more interested in their edit count than ensuring an accurate, and easily readable article for an audience at any level of comprehension. But if you have a substantive opinion on the topic, other than insisting on some magical agreement all English speakers apparently have, please do share with the rest of the class. Marrew (talk) 22:20, 16 August 2022 (UTC)

Criticism

IMO there should be a section on the flaws and imperfections of the system.

Unfortunately it is hard to find sources that don't have a thinly-veiled agenda, so I compiled a list a a starting point:

https://www.reddit.com/r/Metric/comments/uh1ii6/a_sound_critique_of_metricsi/ Musaran (talk) 12:18, 26 August 2022 (UTC)

Personal views and reddits aren't reliable sources. Case in point, Watt-hours and km/h aren't SI units. Minutes and seconds of arc are also not SI units. Headbomb {t · c · p · b} 14:38, 26 August 2022 (UTC)

We still have some legacy "Criticism" sections on Wikipedia, but by and large they're being removed. They tend to become or even start as random grab-bags and breaches of WP:NPOV, WP:UNDUE, WP:SYNTH, WP:OR and more. NebY (talk) 14:52, 26 August 2022 (UTC)

The metrology journal Metrologia regularly publishes articles on potential improvements of the SI, which by definition are criticisms. Citing those would reduce the risk of OR or NPOV. There would remain a clear element of UNDUE, but careful wording might be enough to steer around that charge. Dondervogel 2 (talk) 12:48, 27 August 2022 (UTC)

Proposals for improvements are not automatically criticisms, let alone "by definition", just as suggestions for enhancing physical structures aren't automatically criticisms of the existing structure. (Yes, some people take all positive suggestions as criticism, some people dress up harsh attacks as kindly suggestions, and most of us can tell the difference.)

We could have a section on ongoing development, so long as we avoided WP:CRYSTAL and giving WP:UNDUE weight or even inclusion to suggestions that are, at least as yet, individual views, early blue-sky thinking, or suchlike. NebY (talk) 13:24, 27 August 2022 (UTC)

I agree you can criticise something without suggesting an improvement. But if something can be improved it cannot have been perfect to begin with, so you can't suggest an improvement without (at least) implying a criticism. A section on ongoing improvements makes sense. Dondervogel 2 (talk) 14:48, 27 August 2022 (UTC)