[whatshisface]

>Can the physical world actually reach zero, or only asymptotically approach it?

Five minutes ago, I had zero apples in my hand. At this exact moment, I have no way of knowing how many apples are in my hand due to signal delay and processing time.

Numbers as we know them are only useful for describing the past, but at that task they can work perfectly.

[femto]

Rather, your brain is telling you that you had zero apples in your hand five minutes ago. Given that any measuring tool (including a brain) is a physical system, isn't it also subject to fundamental uncertainty?

Granted that the probability is negligibly small for uncertainty causing two measuring devices (such as my brain and yours) to return different answers for how many apples were in your hand five minutes ago, but is it truly zero?

Also granted that in practical terms it's not worth arguing over, and I don't propose that such possibilities should be taken into account in everyday life.

[whatshisface]

We may have flawed measuring devices, but they are attempting to measure something with a real, constant value. The fact that we are not directly connected to reality doesn't mean that reality is an illusion.

If, in reality, there were zero apples in my hand, I could say that I was holding one apple, but then I would be wrong.