e and π themselves cannot exist in nature (per our current understanding) because our current reality isn't infinitely precise so any circle that exists won't be a perfect circle.
How is that relevant?
We didn't ask if someone can consider or see with naked eye something that looks like a circle, but whether circles do exist in nature.
And we have the "scientific instruments" to check up on the sun (which has a very small, but existing, buldge in the equator, and which also has an uneven exterior with flares and all kinds of motion).
>Wherever did we get the idea of 'circle' from then?
From objects resembling circles, like cut tree trunks, the moon at night, and so on.
Same place we got the idea of line, while there are no lines in nature (for one, because everything we see line-like, is just a line segment: lines extend to infinity).
Or if we could somehow see cross-sections of atoms are elliptical and not circular too?
If so, how do you know that?
Missed the part where the sun's surface also isn't seamless, but an"uneven exterior with flares and all kinds of motion"?
>Or if we could somehow see cross-sections of atoms are elliptical and not circular too?
I seriously doubt it, as from what we know atoms don't look like little balls and aren't solid objects themselves -- they consist of electrons, protons, and neutrons, in orbits, and are "fuzzy". They're drawn as little balls for illustration purposes.