[smegel]

> The number zero was considered useless

It still is as far as I can tell. Try adding/subtracting it - it makes no difference. Multiplying it just gets you back the same useless number no matter what. Dividing by zero? Don't even go there!

[bitops]

I can't tell if you're trolling or being willfully ignorant?

Zero represents the state of "nothingness" - the universe before anything exists. The blank slate, tabula rasa, etc. The empty page before you write anything it.

Zero is a very deep concept and it is far from useless. See the book "Zero: history of a dangerous number".

[femto]

Being funny I think.

I'd think it's actually a valid point though, if the question is put in the form: Does zero (or its reciprocal) have any existence beyond being a useful theoretical construct? Can the physical world actually reach zero, or only asymptotically approach it?

Is the universe infinitely big? Can infinitely small things exist? Can a thing be said not to exist (ie. we have zero of it), or is there always a miniscule probability of it spontaneously appearing due to quantum effects? Is a vacuum really empty? If we have zero, how do we measure it in the face of quantum uncertainty? And so on...

---

Edit: grammar

[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.