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Ask HN: What does 12:00 AM mean?

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Re: Ask HN: What does 12:00 AM mean?

#181

Post by micromacrofoot »

thfuran wrote: post #151
micromacrofoot wrote: post #147

Earlier quoted context omitted.

Unless you're someone's physician you can't really make an assessment that would allow you to determine if someone is intellectually disabled, so don't use it as an insult.

Am I allowed to allege that someone or some act was negligent without being a lawyer? Can I call someone incompetent without performing a study?

Criticize the act on the merits of the act, but don't use a physical condition as an insult. I don't think it's as hard as you make it out to be.

For example, I could say that you're ignorant of the harm that the colloquial use of "retarded" has on disabled people. I could say that you're being needlessly obtuse or selfish by claiming that you should be able to call things "retarded" despite polite requests to stop. I could say that you're callously dismissive of disabled people who are asking for you to stop using the word "retarded" as an insult.

Re: Ask HN: What does 12:00 AM mean?

#182

Post by micromacrofoot »

maydup-nem wrote: post #156
micromacrofoot wrote: post #147

Earlier quoted context omitted.

Unless you're someone's physician you can't really make an assessment that would allow you to determine if someone is intellectually disabled, so don't use it as an insult.

Quoted post unavailable.

viable alternative is to not use intellectual disability as an insult, call someone ignorant if you must

Re: Ask HN: What does 12:00 AM mean?

#183

Post by seba_dos1 »

softwarebeware wrote: post #160
seba_dos1 wrote: post #137

Earlier quoted context omitted.

The difference is that in 12-hour system, the rollover point is ambiguous and non-intuitive (11 PM -> 12 AM -> 1 AM), while in 24-hour one it's perfectly clear and obvious.

The 24 hour system: 23 -> 0 -> 1 How is that different than 11 -> 12 > 1 ? Yes I get it that in normal integers, 1 is not after 12, but neither is 0 after 23.

You're missing the most important bit - the one this whole thread is about.

The 24 hour system: 23 -> 0 -> 1

The 12 hour system: 11 PM -> 12 AM -> 1 AM

In the 24 hour system, there's a single point where the new day starts, and it's the transition from 23 to 0.

In the 12 hour system, where does the new day start? Numbers tell you it's 12 -> 1, but it's actually 11 -> 12. You have no way to figure the answer to OP's question out without additional context.

As others already pointed out in this thread, a 12 hour system using 0 instead of 12 would make it much more intuitive, although now you'd end up with either using 0:00 PM for noon, which feels strange, or using 0:00 AM and 12:00 PM, which is inconsistent. The 24 hour system has no such issues and has a massive advantage over creating new systems - people are already familiar with it.

Re: Ask HN: What does 12:00 AM mean?

#184

Post by mauvehaus »

martin_a wrote: post #62
mauvehaus wrote: post #22

The way to remember this that finally clicked for me is that 'A' means 'ante', 'P' means 'post', and 'M' means Meridian some Latin word that means the sun is directly overhead. Or more practically speaking: noon. 12:00 PM is noon because one minute later, the sun is past being directly above. That is, it's 12:01 Post Meridiem. Since it would obviously be nonsensical for 12:00 AM to be immediately followed by 12:01 PM…

Does not make any sense at all. You jump from "sun is overhead in 12 hours" (12 AM) to "sun is overhead in 1 hour" (1 AM) when you follow that logic. The 12 hour-system is broken and should go away.

Uh, doesn't 1:00 AM mean the sun is overhead in 11 hours?

Re: Ask HN: What does 12:00 AM mean?

#185

Post by [deleted] »

prmoustache wrote: post #60
MrRadar wrote: post #18

Look at an analog 12-hour clock. Ask yourself what the "natural" way to read it at midnight would be (what number is the hour hand pointing towards)?

I don't think it is a usable way to make a european grasp that. Analog clock or not, for all of us 12 is 12 only at noon, otherwise it is 0. The Ante Meridian / Post Meridian explanation works better. Still, it is a fucked way to say time. By the way 24h analog clocks exist too.

[deleted]

Re: Ask HN: What does 12:00 AM mean?

#186

Post by micromacrofoot »

maydup-nem wrote: post #172
micromacrofoot wrote: post #108

Earlier quoted context omitted.

Quoted post unavailable.

Quoted post unavailable.

please refer to the guidelines https://news.ycombinator.com/newsguidelines.html

> When disagreeing, please reply to the argument instead of calling names.

Re: Ask HN: What does 12:00 AM mean?

#187

Post by softwarebeware »

seba_dos1 wrote: post #183
softwarebeware wrote: post #160

Earlier quoted context omitted.

The 24 hour system: 23 -> 0 -> 1 How is that different than 11 -> 12 > 1 ? Yes I get it that in normal integers, 1 is not after 12, but neither is 0 after 23.

You're missing the most important bit - the one this whole thread is about. The 24 hour system: 23 -> 0 -> 1 The 12 hour system: 11 PM -> 12 AM -> 1 AM In the 24 hour system, there's a single point where the new day starts, and it's the transition from 23 to 0. In the 12 hour system, where does the new day start? Numbers tell you it's 12 -> 1, but it's actually 11 -> 12. You have no way to figure the answer to OP's q…

> "where does the new day start?"

I honestly am trying to understand the point being made. Isn't when the day starts obvious in either case? We know when the new _day_ starts because the date rolls over at that time. No one thinks the day starts at 12:00 in the 24-hour system, or 12:00pm / noon in the 12-hour system?

> ... there's a single point where the new day starts ...

Is this what you're saying: that in the 24 hour system, there's one point in time where the clock resets from a high number to zero, and that's also when the day starts. Therefore, it is "not confusing."

I felt rather that the problem the OP stated was simply "I am used to the 24 hour system and I was communicating with someone who was used to the 12 hour system. They naturally gave me a time of 12:00am but I didn't notice that am part and assumed they meant the same "12" that I understand as "12" in my system. So I missed an exam."

Re: Ask HN: What does 12:00 AM mean?

#188

Post by sjs382 »

xiwenc wrote: post #171
njkleiner wrote: post #116

Okay, I'm genuinely confused now, can someone please explain this to me? First of all, how is nobody taking about the fact that OP was scheduled for an exam that takes place... at midnight. There are two possible cases here. Some people are alleging that OP lives in the same place as the exam takes place -- which is not clear to me from the information available -- and use this as an excuse for saying "OP should adop…

OP here. The online exam is run by Pearson Vue. With my brief research I found it’s a British company. That could be the reason they use AM/PM. I think with better UX on their scheduling app this would have been avoided. Imagine how much cost they could save with minor improvement. It wasted the proctors, customer service and my time. Unless they don't acknowledge own fault and require customers to pay for another ex…

I hope this doesn't come off as unnecessarily combative, but the real solution here is to check, verify, double-check and triple-check when presented with notation that's unfamiliar with you.

> How do we solve this more universally?

It's not a universal problem. While entire cultures and countries /could/ invest resources changing (and more people experience confusion centered around any transition), it really isn't a problem for most. And when it is, it's unlikely to be a problem a second time. Once bit, twice shy.

Re: Ask HN: What does 12:00 AM mean?

#189

Post by seba_dos1 »

softwarebeware wrote: post #187
seba_dos1 wrote: post #183

Earlier quoted context omitted.

You're missing the most important bit - the one this whole thread is about. The 24 hour system: 23 -> 0 -> 1 The 12 hour system: 11 PM -> 12 AM -> 1 AM In the 24 hour system, there's a single point where the new day starts, and it's the transition from 23 to 0. In the 12 hour system, where does the new day start? Numbers tell you it's 12 -> 1, but it's actually 11 -> 12. You have no way to figure the answer to OP's q…

> "where does the new day start?" I honestly am trying to understand the point being made. Isn't when the day starts obvious in either case? We know when the new _day_ starts because the date rolls over at that time. No one thinks the day starts at 12:00 in the 24-hour system, or 12:00pm / noon in the 12-hour system? > ... there's a single point where the new day starts ... Is this what you're saying: that in the 24…

> We know when the new _day_ starts because the date rolls over at that time.

That's an additional reasoning you have to do in order to explain the non-intuitive fact that the new day starts when transitioning between hour 11 and 12. You can't come up with that conclusion based on clock system alone, you need to reach for the calendar. It makes you jump additional mental hoops, making it error prone (as evidenced by this thread).

> but I didn't notice that am part and assumed they meant the same "12" that I understand as "12" in my system

No, people who use 24 hour system are usually familiar with 12 hour system as well (guess what's there on analog clocks?). It's just this one special case of 12 AM/PM that's confusing, because you can make convincing arguments for having it both ways.

Re: Ask HN: What does 12:00 AM mean?

#190

Post by orev »

technobabbler wrote: post #58
Quikinterp wrote: post #5

A lot of my exams will use the time 11:59pm instead of 12:00am to avoid confusion like this

That doesn't help people who don't know what am/pm are. 11:59pm would be 23.59 in some places (like Finland). It's possible to mix up dates and times from each other too (is 12.30 Dec 30 or half past noon?)

11:59 pm is 23:59 by all definitions.

Why GP would have exams at midnight is anyone’s guess, but the example can only be interpreted as just before midnight.

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