0deg F was originally set as the freezing point of sea ice, which could be recreated in the lab using a mixture that's more thermally stable than the freezing p

0deg F was originally set as the freezing point of sea ice, which could be recreated in the lab using a mixture that's more thermally stable than the freezing point of fresh water. Not as arbitrary as people think. Most units have a good reason for their definition, in the context for which they're used, and are divisible by numbers that are convenient. Without needing decimals at all. And in my experience, the people who benefit from base 10 metric are the same people who misplace decimal points.