the clock and the AM/PM system makes much more sense when you count from 0.

0am 1am 2am 3am … 11am

0pm 1pm 2pm 3pm … 11pm

instead of:

12am 1am 2am 3am … 11am

12pm 1pm 2pm 3pm … 11pm

the ancient people that invented the clock were programmers all along??

you may find comfort in knowing that in a mathematical sense, they’re the same. this is because 12 hour clocks use modular arithmetic. doing arithmetic modulo 12 is basically the same thing as doing normal arithmetic with the whole numbers, except you add in the rule 12=0. for example, modulo 12, we have 15 = 3 + 12 = 0 + 3 = 3. (this explanation of modular arithmetic comes from viewing it as “normal addition” in a quotient ring.)

this is all a long winded and overly technical way of saying that it’s completely reasonable to say that 0am and 12am are the same thing.

This, basically a lot of things were based on 12 in the olden times. But since the French were against everything British, including their imperial system they based their metric system on base 10. I heard there were even clocks in France that had only 10 hours