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> as we argued about the same topic yesterday I replied to one of your comments in a topic that was not [1] and not even obviously related. Additionally there
by raattgift 10y ago
> as we argued about the same topic yesterday
I replied to one of your comments in a topic that was not [1] and not even obviously related. Additionally there was no argument as you did not reply. So I'm thoroughly confused by your implied context.
I'm a wishy-washy formalist and know some things about Boltzmann Brains as a theoretical diagnostic on de Sitter universes with slow-rolling inflationary fields, so I'm OK with your last two italicized paragraphs ("This is why I asked..." and "If we added a..."), but completely disagree with your subsequent non-italicized text.
In particular, geometry is a feature of nature. The Earth is round to a close approximation, and that is an observer-independent fact, not a convention.
> Does that mean that grains of sand include most of mathematics?
Of course not, but grains of sand include atoms and subatomic particles and those have features that are the same in non-sand substances in the various parts of the the solar system we have directly explored. We can describe those features in whatever language we want; but names, like sets of coordinates, are not features of nature.
Indeed, in the past century we've gotten much better at distinguishing between features which are observer-dependent (even if not obviously so) and features which are not.
In your sand argument, the pile of sand has some observer-independent features and some which are not. The number of the grains of sand in the pile is an observer-independent quantity, even if nobody actually counts them.
Formal models may be incorrect, but physical (as in not unphysical) ones attempt to describe real observer-independent features of nature. I don't think there are many physicists who, arriving at a novel prediction of a formal mode, would do anything other than "trust (or mistrust) but verify"; even the craziest model-building theoreticians I can think of are hungry for contact with nature via controlled experiment.