Originally Posted by

**Jarhyn**
... there is a maximum specific meaningful precision to the speed of light. And even of G.

So, is there a set that can be described, but not calculated, that is not merely "measured" and thus finite in complexity given a finite reference frame?

I'm not clear on the question. I think you're distinguishing between "mathematical numbers" and (the ratios of) physical measurements. Is that correct?

Nitpick: The speed of light in SI meters per SI second is known

*exactly*!

Originally Posted by

**Système international (d'unités)**
The metre (meter) is currently defined as the length of the path traveled by light in a vacuum in 1/299,792,458 of a second.

The second is defined as being equal to the time duration of 9,192,631,770 periods of the radiation corresponding to the transition between the two hyperfine levels of the fundamental unperturbed ground-state of the caesium-133 atom.

Until 2019 the SI kilogram was a hold-out, being defined as the mass of a certain platinum-iridium cylinder in a certain climate-controlled French vault (which was slowly evaporating!). But just as the meter is now

*defined* by fixing the speed of light to be a specific finite constant, so the kilogram is now defined as whatever it needs to be to make Planck's Constant = 6.62607015×10

^{-34} kg m

^{2}s

^{-1} exactly.