If you’ve got a building that has only basement levels aside from the ground floor, I feel like the first basement level being the “second floor” is completely valid. The reason we usually use a different system for basement floors is because there’s already a second floor that isn’t the first basement level.
Meanwhile just pure rational (mathematical even) +/- X from ground floor is logic all the way around
If we want to be purely mathematically rational then we’re either using the US system where the ground floor is the first floor or we’re using the Russian system where the ground floor is floor 0. Either way, we need to acknowledge that the ground floor is the start of the count. You can’t just say it’s not a floor because it happens to be the place where you entered.
If you’ve got a building that has only basement levels aside from the ground floor, I feel like the first basement level being the “second floor” is completely valid. The reason we usually use a different system for basement floors is because there’s already a second floor that isn’t the first basement level.
If we want to be purely mathematically rational then we’re either using the US system where the ground floor is the first floor or we’re using the Russian system where the ground floor is floor 0. Either way, we need to acknowledge that the ground floor is the start of the count. You can’t just say it’s not a floor because it happens to be the place where you entered.