Why Base 60?

 

I have a few related conjectures as to why the Babylonians used a base 60 counting method. Thinking of our own society and the fact that we use a base 60 counting system for time, I wonder if this is a holdover from ancient time measurement. I recall hearing a story about the Egyptians developing a calendar using base 60 partially because they had a notion of a 360 degree circle, which divided evenly into 60. This story was accompanied by a myth about Nut winning five days of light from the moon god, which explained why there were 365 days in the year (rather than the more mathematically perfect 360). 

This explanation based on time would also make sense because of the difference between 10 and 60. As we discussed in class, 60 has more small factors; while 10 has only 1,2,5,10, sixty is a product of 1,2,3,4,5,6! This would be very useful when making fractional measurements. 

Having done some research, I realize that the error in my thinking lay in my attempt to determine why base 60 would be useful, not why it would arise. Systems are rarely designed perfectly, but rather the result of convenient choices over time that gained inertia. From my reading, it appears that the Babylonian base 60 system was a combination of base 5 and base 12 systems used by different groups in Ancient Mesopotamia. In order for them to communicate numerical information, they used the lowest common base, 60. The origins of those two earlier systems is not entirely clear, but some reading suggests base 5 was centred around fingers on a hand, while base 12 was the result of counting digits on fingers.