| daniel added a comment. |
In T142087#2610204, @Ladsgroup wrote:(e.g. for measurements, which are never absolutely exact).
Measurements can be exact. Two examples:
- Speed of light is exactly 299,792,458 meters / second. Because definition of meter is derived from the speed of light.
That's a definition, not a measurement.
So yea, not all values of the speed property are going to be actual measurements; there can be absolutely exact values for speed that are not measurements. But that's a rare edge case, rather than the rule. I cannot think of a property where it would be equally likely for the value to be a measurement or a definition.
- Spin of electron is exactly half of Plank's constant.
That's a theoretical result (confirmed by inexact measurements). But spin is kind of special anyway, since it's not a continuum, as far as I know.
What I mean is that being exact or not is highly dependent on unit measured and that needs to be taken into consideration.
You are right that it is not necessarily the same for all Statements for a given property - speed is not always a measurement. So stripping +/-0 from all values for speed is going to be wrong in some cases. But it's going to be correct in far more cases. The cases in which the speed is not a measurement can probably be found and managed by hand, since it's a rare case .
Cc: Lokal_Profil, Ladsgroup, Edgars2007, Pasleim, Aklapper, thiemowmde, daniel, Lydia_Pintscher, D3r1ck01, Izno, Wikidata-bugs, aude, Mbch331
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