4 ms·
Actually the reason we have base-60 time is that we have 5 fingers on one hand, and 12 knuckles that can be pointed to by the thumb on the other. 5x12=60. Of c
by garmaine 7y ago
Actually the reason we have base-60 time is that we have 5 fingers on one hand, and 12 knuckles that can be pointed to by the thumb on the other. 5x12=60.
Of course why the Babylonians went with this two-mechanism system instead of doing the same thing on both hands is probably because of divisibility. Get a prime factor of 5 from one hand, and prime factors of 2 and 3 from the other.
(Also note that you can count 12 hours on one hand, a full 24 on both.)
EDIT: AFAIK the Babylonians didn't have a developed number theory, and I'm not sure they even had a formal idea of prime numbers. But we do know from surviving accounting "textbooks" (practice tablets & instructions) that both they and the near-contemporary ancient Egyptians understood the special divisibility of these numbers.
- jarfil 7y agoIf binary has taught me anything, is that you can count up to 1024 with 10 fingers...
- masklinn 7y agoIf you've got flexible hands and independent-enough fingers you can even count in ternary, up to 59048 (though binary can also take advantage of toes for a limit of 1048573)
- Anarch157a 7y agoUsing your hands to signal 4 in binary could put you in a lot of trouble.
- rakoo 7y agoNot a single person I've met has ever used knuckles as a way to count anything, especially time.
- garmaine 7y agoYou obviously haven’t lived in ancient Babylonia. (Pro tip: different cultures have done things differently across time and space!)
- jacobolus 7y agoI have not seen any evidence that ancient Mesopotamians counted phalanges using their thumbs. I believe that counting method was devised by some fan of duodecimal arithmetic sometime within the past century, and has nothing to do with sexagesimal numeration per se.
- garmaine 7y agoIt’s visually built into the cuneiform: https://en.m.wikipedia.org/wiki/Babylonian_numerals https://en.m.wikipedia.org/wiki/Babylonian_numerals
- jacobolus 7y agoIf that is your evidence then you are tricking yourself, or to be generous speculating wildly. The evolution here was: physical clay counters; physical clay counters sealed in a clay envelope; physical clay counters sealed in a clay envelope but also pressed into the outside of the envelope to indicate how many; clay tablet with counters pressed into the outside (since the envelopes with counters inside were redundant); clay tablets with little cuneiform symbols to represent quantities, differing by type of object being counted, and not all sexagesimal; more uniform written sexagesimal writing system. There is no indication in the symbols about how people counted on their fingers.