[zkmon]

Seeing book sections or chapters starting with zero, always confuses me. I know that this convention is probably inspired by the fact that the addresses of memory locations start with zero. But that case was due to that fact one of the combination of the voltages can be all zeros. So, it's actually the count of combinations, and I don't think it can be used for ordinal enumeration of worldly things such as book chapters, or while talking about the spans in space and time (decades, centuries, miles etc). There is no zeroth century, there is no zeroth mile and there is no zeroth chapter. In case the chapter numbers are not meant be ordinal, then I think it would be odd to call Chapter 3 as fourth chapter.

[asimpletune]

If you’re at a corner and someone asks for directions, you say “three blocks that way”. That means three blocks starting from here.

Then what do you call “here”?

The name for where you start from in this scenario is usually not required because it’s obvious what you mean and everyone understands the first block means you have to first walk a block, not that where you start is the first block.

So in that sense yes we have a zeroth chapter. That’s when you’re at the beginning of the first one but haven’t read all the way.

[oh_my_goodness]

Folks ... cardinal and ordinal numbers both have "just so" stories to support them. We're unlikely to eliminate either one of them today.

[zkmon]

"here" is definitely not a zeroth block. As soon you start walking, you are in the first block. However, if you are numbering the separations (cuts) between the blocks, you can number that "here" as zero.

[asimpletune]

Ok as soon as you start walking your are in the first block, I agree. So then where are you before that? What block were you at before you started moving, when you were giving directions?

What is the name of the block from which you left to enter the first block? Before you started walking I mean.

And mustn’t that block be before that other first? When we move from where we start we count up, so then mustn’t an earlier block be counting down? Counting down would mean a number smaller than one.

And are blocks not counted in units, as whole numbers?

So would it not be the case that one block less than 1 must be by necessity the zeroth block?

In other words if you agree that “as soon as you start walking, you are in the first block”, then you must also agree that before you left you began in the zeroth block.

How else could it be interpreted?

[zkmon]

Before starting to walk, you were at the start of the first block, not at zeroth block. There is no block prior to first block. Otherwise that block would be called as first block.

Think of jogging on a road. When you are at the beginning of the road, you are at the start of the first mile, not in the zeroth mile. It doesn't have one more mile prior to first mile.

[asimpletune]

O you’re right. How could I forget the first minute of each day is 12:01, or that a previously unknown computer exploit is called a 1-day exploit.

And everybody knows a pandemic starts with patient 1!

[bazoom42]

The patient-0 terminology arose from a misreading of the label patient-O, where O is the letter O.

When numbering discrete elements you usually start with 1, so first is 1, second is 2 etc.

Indexes in C are not ordinal numbers though, they should be thought of as offsets or distances from the first element. So [0] is 0 steps away from the first element, hence the first element. The confusion arise when you think these indices are actually ordinal numbers.

[lionkor]

The first element in a collection at address 15 is at address 15. The offset of an element from the start is addr-start, so 15-15=0 for the first, 16-15=1 for the second, etc.

that's why we start from 0, not because of voltages, at least in compsci.

[zkmon]

This is all mostly about cuts and spans in a continuum. Cuts can be numbered starting with zero, but spans can't be. Book chapters are spans of content.

[griffzhowl]

Usually the chapter 0 is preliminary or prerequisite material. It makes sense in an obvious and intuitive way if you want an ordinal "before the first", even if that sense isn't a rigorous mathematical one (although I think there's no problem with it).

I guess the practice was influenced by computer science - I don't know of an example that precedes it, but one fairly early one I've found is Bishop and Goldberg's Tensor Analysis on Manifolds from 1968, with a chapter 0 on set theory and topology. Back then the authors felt the need to justify their numbering in the preface:

"The initial chapter has been numbered 0 because it logically precedes the main topics"

Quite straightforward.

There's also the "zeroth law of thermodynamics", which was explicitly identified long after the first, second, and third laws, but was felt more primary or basic, hence the need for an "ordinal before the first"

[zkmon]

Hopefully they don't discover another more fundamental law, to be called as "minus oneth" law

[griffzhowl]

Indeed

[danmaz74]

The reason is that, for an array (or vector), you find the memory position for the i-th element with the base address + i*word_length. And the first element is in the base address - so has index 0.

[Jtsummers]

It has memory offset 0, which we use as the array index for convenience so that there's no distinction between a memory offset-base and the corresponding array index-base. That's what happens when your arrays are barely different from pointers, as in C. If your arrays aren't just a stand-in for raw pointers, then there's little reason to require 0-based indexing. You can use more natural indexes based on your particular application, and many languages do allow arbitrary indices.

[aaaronic]

Building floor numbers in at least a few countries I’m aware of start from zero or “G” ( or the local language equivalent for “ground“) with 1 being the first story above the ground.

I think you’re just biased to think that starting must “naturally” begin with 1.

Zero is just a good a place to start and some people do start counting from zero.

[zkmon]

The floor number case arises so because traditionally it is the count of "built" floors. So, ground is technically not a floor in that sense. Also, if the floor indicates a separation (cut) between the living spaces, ground floor can be numbered as zero, just like the start point of a measuring tape is numbered as zero.

[1718627440]

There are countries that don't? Do they just skip a number and go -2, -1, 1, 2, ...?

[64718283661]

A zeroeth century sounds reasonable to me.

[moron4hire]

Dijkstra wrote a rather famous screed against 1-based indexing, so it's more of an inside joke.

You're also wrong about there being no 0th mile. https://www.atlasobscura.com/places/u-s-route-1-mile-0-sign

[hollerith]

There is however the zeroth element of a vector in most programming languages.

[zkmon]

Zero is not an ordinal number. There can be a vector element indexed with zero, but it is not "zeroth" element. Book chapter numbers are ordinal numbers.

[vouwfietsman]

But what is there to gain with this distinction?

Just the convenience of having an ordinal number to say? Rather than saying "chapter 0, chapter 1, chapter 2" one can say "the fourth chapter"? Or is it the fact that the chapter with number 4 has 3 chapters preceding it?

On first glance I find this all rather meaningless pedantry.

[oh_my_goodness]

If I use ordinal numbers to count, then counting tells me the number of objects. Sometimes I want to know the number of objects.

EDIT: Yeah, I don't know why book chapter labels shouldn't start with "0". It seems fine to me. They could use letters instead of numbers for all I care.

[zkmon]

If they use letters instead of numbers, note that letter "A" is the first alphabet, not zeroth alphabet.

[oh_my_goodness]

When I'm counting letters it's more convenient to go "one, two, three." When I'm finding the offset between letters it's more convenient to go "zero, one, two." Neither of these methods is going to displace the other.

Definitions are fine, and I agree that "A" is the first letter. But that's no use to people who need to think clearly about the offset between "A" and "C" right now. Should I tell them they're wrong, they have to count to three and then subtract one? Because the dictionary says so?