How do you measure absence?
What do you mean? Like, how long someone is gone?
I mean just absence, period. Nothingness. The lack of something.
Zero? Null quantity?
Zero, that's the one I was going for.
You could have just opened with that.
Not as fun, though.
Do you know who invented the concept of zero?
Didn't Arabs do that while Europe was in the Dark Ages or something?
No, actually! Though they did introduce it to Europe. The Arabs got it from India. Sumerians were recorded to have invented it first, though it's not clear that anyone else learned of it from them. India may have independently come up with it, and Arab merchants picked it up from them. The Mayans also invented it on their own, I should add. You'd think it's a natural concept, but plenty of cultures got by without any concept of a "null quantity."
Rather than being widely accepted once people heard of it, there was actually a lot of resistance. I guess that's not too surprising. Lots of people hate being confronted with new things, even if they are very useful.
What's interesting is that everyone didn't come up with exactly the same kind of zero. The ancient Egyptians had a hieroglyph used when an account's balance completely zeroed out, but it's unclear whether it meant "zero" in the way we think of it now. It probably didn't. The ancient Babylonians used a base 60 number system and for positional numbers that had no quantity--think the zeroes in "1000"--they just used spaces. Obviously, that's not ideal, especially if you have consecutive spaces.
This is all very fascinating...
But you want me to get to the point, right?
Humans are obsessed with nothingness. I don't mean the nothingness of death. I think I talk about that enough already. But the nothingness of... nothing. If I have zero apples in my hand, it doesn't mean I have some very small number of apples, it means in my current frame of reference--namely, my hand--apples do not exist at all.
What's interesting to me is we have expanded this concept of a null quantity to encompass all kinds of things. It represents a false boolean value, it's one of the two possible values in a binary number system. Speaking of, the entire reason computers operate in binary is because the easiest system to implement was essentially switches that were either "on" or "off." On is 1, off is 0. Simple. But in that context, it doesn't really represent a null quantity, necessarily. It's more of an opposing quantity. It's either this or that. One or the other.
I think that hints at what zero really is: it's not just a nothing, it's the opposite of something. Everywhere else in math, you have a positive quantity or a negative quantity. Zero stands in opposition to all of those. It is neither. It cannot be anything else. It has one job, yet it might be the most important job in all of computation, in that it presents a symbol for opposing the normal operation of all others. After all, if you multiply by zero, you get zero. They say you can't divide by zero but it's more that the value is undefined. There's no concept in math that would help you divide by nothing. There might be novel mathematical systems that permit it in some way--not sure how that would work, but maybe somebody's got ideas. But, as it stands, it's indivisible.
And of course, if you add or subtract zero... nothing happens. Then there's using zero as an exponent, which always equals one, for reasons that don't have anything to do with zero itself, so I suppose that doesn't really count.
I still feel like you haven't made a point.
Fine, fine. The point is a nothingness that isn't just where something used to be, but which stands against "somethingness" completely. Think about all the timelines I've told you about--the ones I've created, merged, tied off, screwed up, saved, etc. But think about everything that could have happened, but didn't. They're just zeroes. They don't exist, they never existed, they never will exist. From the right perspective, every timeline, every possibility that could ever exist, already does exist. Anything outside of that is just a null quantity. An impossibility. A never-happened, a never-will-happen. And sometimes I feel like there should be a special zero for that, a "super zero" or "meta zero" to represent that total antithesis to anything.
Sounds almost like a black hole. I mean, not that a black hole is literally a number, just that it does represent a literal nothing. Which is funny to think about because there's definitely something inside it, but it's inaccessible.
And when it evaporates, whatever was inside is emitted in unrecognizable form, which upholds the idea that no information can enter or leave a black hole. Anything that enters it is fundamentally altered--and so is anything that leaves it.
But that's not really a zero, is it? I mean, it's not truly nothingness.
But in another sense, maybe it is. It completely destroys whatever it was before. And from the perspective of either side of the black hole, anything that passes the event horizon is simply gone forever, neutralized as if it never existed, apart from the mass conservation.
Getting existential on me, eh?
Am I ever not existential? Think about my life, here! It's just one giant existential crisis... or maybe an endless cluster of them, all spiraling out together. It's not not an existential crisis, that's for sure.
It's a nonzero quantity of existential crises.