This topic has been done to death, but ah, what the hell *shrugs.
I would say 0.999> is as close to being 1 as you can possibly be, without being 1.
Why?
Simply because they aren’t exactly the same, only 1 can be 1, only x can be x.
Maybe 0.999> is so close to being 1 that for all intensive purposes it might as well be 1, but strictly speaking it’s not.
Maybe it would help to visualize what 0.999> would even look like in nature?
Could 0.999> even exist in nature?
Can matter and space be infinitely small/big?
Perhaps we will never know.
Assuming they can, what would a domino that’s 0.999> centimeters in height look like, and is it equivalent to a domino that’s 1 cm in height?
Place the two dominos on a perfectly flat, perfectly level table.
You should be able to wave your hand 1 cm above and over the table without touching the 0.999> cm domino and knocking it over, but you shouldn’t be able to wave your hand 1 cm above and over the table without touching the 1 cm domino and knocking it over.
That would be the real world empirical, tangible difference between something that’s 1 cm, versus something that’s anything less, whether it’s 0.1 cm less, or 0.01 cm less, or even 0.000> cm less than 1.
However, if your hand is any closer to the table than 1 cm away from it, even just the teeniest, tiniest bit, you will touch both the 1 cm domino, and the 0.99> cm domino, as you wave your hand over the table, knocking them both over, because 0.999> is as close to being 1 as you possibly can come without being 1, so anything closer than 1 cm away, even if it’s only 0.0000000001 cm closer less is going to be within its range to interact with it.
…Or maybe at that distance your hand will pass over both of them, without touching them, but it should be possible to place your hand at a distance from the table, so the bottom of it occupies the same space as the top of the 1 cm domino, but not the 0.999> domino, so you’ll be able to knock the former over at that distance, but not the latter.