Talk:Q12457

Merge? --Fractaler (talk) 12:16, 26 October 2016 (UTC)[reply]

@DeFacto: As far as I can see, there is no consensus in the literature as to exactly what constitutes the "metric system". All writers are agreed that the metric system is a decimal-based system that uses the kilogram, metre and second (or decimal multiples or submultiples thereof) as the base units of mass, length and time respectively. Most authorities agree that during the 19th century the metric system was extended to include electrical quantities. However, as you are aware, at least three coherent systems emerged to describe electrical qantities - the esu system, the emu system and the practical system and at least cohernet systems two (cgs and MKS) to describe mnechanical quantities. Different authorities had different ways of linking these systems withitn the metric system. The most influential authorities, such as the CIPM (who wrote the SI Brochure) avoided formally relating the SI, cgs, MKS, esu or emu systems to the term "metric system". A few authorites wrote of metric systems (plural), while others wrote of "flavours/variants/manifestation of the metric system". In 2007 the "metric system" was legally defined in the United States as being "SI". We therefore have no authoritative statement as to whether there is only one metric system or multiple metric systems, let alone whether SI and the "metric system" are identical, whether one is a subset of the other etc. Martinvl (talk) 21:38, 26 September 2020 (UTC)[reply]

@Martinvl: you have convinced me that, quite surprisingly, it is not clear-cut. Thanks. DeFacto (talk) 08:59, 28 September 2020 (UTC)[reply]

@DeFacto, Infovarius: In order to clarify the relationship of the "metric system" to other systems of units that use the [kilo]metre and [kilo]gram as their base units of length and mass, I think that we need to familiarise ourselves with Section 1 of the International Vocabulary of Metrology 2012 (VIM) (International Vocabulary of Metrology) and in particular

• 1.13 system of units
• 1.14 coherent system of units
• 1.16 International System of Units.

It should be noted that although the VIM mentions SI, it does not mention any other systems of units. We need to clarify which authorities asseted that there were multiple metric systems and whether, in view of the publication of VIM in 2012, their assertions still hold. We also need to see which authorities asserted that there was only one metric system, and again see how they related their assertion to SI, cgs, cgs-emu, cgs-esu etc. Martinvl (talk) 20:48, 28 September 2020 (UTC)[reply]

@Martinvl: that VIM document doesn't mention 'metric system' at all, so doesn't really inform this discussion. DeFacto (talk) 14:29, 29 September 2020 (UTC)[reply]

@DeFacto: I know it doesn't, but it clarifies the langauge used - in particular it clarifies that a "coherent system of units" is a subclass of a "system of units" and that these are the terms that should be used in a discussion. Martinvl (talk) 17:43, 29 September 2020 (UTC)[reply]

@Martinvl: so we need to look elsewhere for support wrt the relationship with the/a metric system. How about the BIPM? Their SI brochure describes the SI as "the modern form of the metric system". And isn't the SI also a coherent system of units? DeFacto (talk) 19:28, 29 September 2020 (UTC)[reply]

@DeFacto: You are quite right, but since we are also interested in the older forms of the metric system, we cannot just use the BIPM definition. However, the BIPM wording "modern form" suggests that the metric system has evolved over time - the French certainly used the term "système métrique" without any further qualifications during the debates to revoke the Mesures Uselles in 1837. Reading through a number of sources that are dedicated to measurements (rather than those that regard measurements as a tool). I was only anble to find one author (from NIST) who wrote of "metric systems" in the plural (but I found two NIST references that definitely used "metric system" in the singular when refering to the cgs variants, SI etc.. I recall that you have quoted from Donald Fenna's book "A Dictionary of Weights, Measures, and Units" (Oxford Press). If you look at the entry for the "metric system" you will see that he wrote "other manifestations include the cgs system, the mks system and an mts system. In other words ONE metric system that shows itself in different ways. Meanwhile, will you please clarify which literaturew you consulted regarding multiple metric systems when you rewrote the Wikipedia article "Metric system" (or was is WP:OR? Martinvl (talk) 21:17, 29 September 2020 (UTC)[reply]

@Martinvl: If the MKS system is one version of the metric system (per its entry in Fenna's dictionary) and the SI is another version of it, doesn't that mean that they are both metric systems? There have been several versions of the BBC logo; this is a BBC logo and this is a BBC logo - they are both BBC logos. DeFacto (talk) 08:16, 30 September 2020 (UTC)[reply]

@DeFacto:Both logos play the same role, they identify the object to which they are attached as being asswociated with teh BBC, as opposed to say ITV, therefore even though they might look a little different, legally both play the same role. Martinvl (talk) 10:58, 30 September 2020 (UTC)[reply]

@Martinvl: yes, they are both BBC logos, two different logos. Like MKS and SI are both metric systems, two different metric systems. Is that what you meant? DeFacto (talk) 11:33, 30 September 2020 (UTC)[reply]

┌────────────────────────────────────────────────────────────────────────────────────────────────────┘ @DeFacto: No - if you read en:Logo of the BBC, you will see that the opening words are "The BBC logo" (Note - singular). Just as there have been a number of different version of the BBC logo, the metric system is also evolving - the modern version (ie SI) is different to the version of 1799, though if you were to calibrate your tape measure or scalepan against the metre des archives or the kilogramme des archives rather than against the speed of light or the Kibble Balance, you would probably not notice the difference (unless you were working to five decimal places). Martinvl (talk) 13:44, 30 September 2020 (UTC)[reply]

@Martinvl: and if you go beyond the first three words of the article you will come across this: "From 1958, for this television network, there are five different logos. The first logo of network is used from 1958 to 1963, the second logo is used from 1963 to 1971, the third logo ..." So, clearly, that confirms that there is more than one BBC Logo.

Now, bearing that in mind, and thinking about the metric systems again... If (as per Fenna's dictionary) the MKS system is considered to be a version of the metric system and the SI another, we must be able to say: since 1799, there have been [number] different metric systems. And then list them... The first, the xxx system was in use from 1799 until [date], the second... and the current one, the SI since 1960 (or whenever). No? DeFacto (talk) 15:04, 30 September 2020 (UTC)[reply]

@DeFacto: To come back to my original question - please give a source that states explicitly that there are multiple metric systems. Martinvl (talk) 23:20, 30 January 2021 (UTC)[reply]