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by atwood22 1390 days ago
No, we don't count from 0. That's like saying we start counting a baker's cup from 0 because you can have half a cup.
7 comments

The counting activity doesn't begin when the first item is registered; it begins when the counter is initialized to zero. A decision is made to begin counting, along with the realization that nothing has been counting yet. That's when counting has started. When the first item is seen, the counting is then continuing.

Suppose your job is to count some events. You check in for work at 8:00 a.m., but the first event has not registered until noon. By your logic you should not be paid for four hours, because you're paid to count, and counting started at 1.

Are you sure?

We are talking about the he numbering, not the work-doing.

You start waiting at 8, and you wait between events. But you only count (increment) when an event happens.

The 0 comes for free when you are ready to count (hello golang and C++, as well as human intuition).

When you count stars in the sky you don't say "0, 1, 2".

You say "..., 1, 2", or if no stars show up, you say "there are 0" after timer expires.

> But you only count (increment) when an event happens.

Increment what?

> When you count stars in the sky you don't say "0, 1, 2".

No, you say, "I'm going to start counting stars now. Okay, 1, 2, ...".

The preparation part is the zero. You counted stars before and reached some number; you're not starting at that number.

You're still thinking like a computer. Most people think of counting in terms of 'here are some apples, how many exactly?'

If you just look at an empty space, the # of apples is equivalent is equivalent to the # of dinosaurs, but they're only equivalent by their absence.

No, the mathematical definition of counting (i.e. whether or not a set is countable) involves mapping to the natural numbers, which doesn’t include 0.
I don't think your definition is complete. We can count a set by mapping its elements to the natural numbers, and then identifying that number which is highest. However, we must have a provision for identifying zero as the highest when the set and mapping are empty.
Math counting doesn't care where you start. You could start -400 if it's useful for the problem
You can name things however you want, but there is a canonical bijection to zero-based ordinals.

https://en.m.wikipedia.org/wiki/Ordinal_number

What counter? You're saying a counter exists before people start counting? Is this a form of mathematical Platonism?
A counter can be lazily instantiated just before the first item is counted.
What does your stopwatch say right now?

Your pedometer?

Your traffic clicker?

Those are devices, not the spoken language.
So if the counter doesn't speak, there is no counting?
What do you do for a living, and why are they paying you not to understand this?
Do you know the definition of countable? A set S is countable if there is a one-to-one mapping from S to N where N is the natural numbers. Do you know that 0 is not a member of the natural numbers? We literally start counting at 1 by definition of countable.
Nope.

Is the empty set countable? (Yes.)

Dictionary:

nat·u·ral num·bers

  the positive integers (whole numbers) 1, 2, 3, etc., and sometimes zero as well

Countable: https://en.wikipedia.org/wiki/Countable_set

Set theory:

https://en.wikipedia.org/wiki/Ordinal_number

From your own link on countable sets:

> Equivalently, a set S is countable if there exists an injective function f : S → N from S to N; it simply means that every element in S corresponds to a different element in N.

Defining N is usually done via a successor set, on which case 0 makes no sense to include.

A successor set is the set of successors of... 0 or 1, depending on what you are doing.
An empty set is countable; it has an empty mapping to the natural numbers. Its cardinality is zero.
And its ordinalitiy is also 0.

Standard construction of ordinals is that each ordinal is the set of all its predecessors. (0 has no predecessors , hence 0 is the empty set.) (And so finite ordinals have the same ordinaliity as cardinality).

Show me a mathematical text where ‘ordinality’ is defined.
Are you a time traveller from the late 17th century?
Can't they just .. disagree?

Birthdays are clearly 1 indexed, the first birthday is indexed with 1, and not with 0.

They day you're born is birthday number 0
Exactly.

Birthday[0] gives you an out of range exception, since there is no birthday called 0th. Birthdays are [first,second,..] indexed from 1: brithday[1] = first, birthday[2] = second, and so on. That's what indexing a series from 1 means.

Ok, use the baker and cup as an example. If you have an empty cup and put half of a cup of flour in it, you now have 0.5 cups of flour. Notice the zero before the ".5". That is us, normal humans, realizing that until you add enough to have 1 of something, you have between 0 and 0.999 repeating.
When I'm baking I start by zeroing the scale, then adding enough flour to reach 500 g (or whatever the recipe calls for). That's counting from zero.
If we (speaking as a North American) count from 1, does that mean other cultures (e.g. Korean) count from 2?
No, it just means we have a different notion of what a year is in regards to age. Similar to how different cultures can use different units of measurement for length, mass, etc.
Yes, exactly. One of which carries an implicit zero indexing. The date of birth doesn't disappear just because you decided to use a different measuring device.
No, it doesn’t carry an implicit 0 index. Measuring age (in the West) is like measuring distance. You start at 0, but that doesn’t mean the first item is at index 0.
If you took a standard ruler, a measurer of distance and which has literal index marks painted on it, and placed items along it, the item found at the head of the ruler would be found at the 0th index. You're quite right that we think of birth and its anniversaries in the same way.
Birthdays are literally indexed by the moment of birth as zero.

You can't possibly be serious.

I start with a empty cup, then I fill it up to 1 cup.

I then put it in an initially empty bowl

Yes this is correct!

The milliliters in a baker's cup are a scale based on 0!