Fahrenheit was not an entirely arbitrary choice: it was defined based on two points of reference that could be measured at the time: the freezing temperature of an ammonium chloride brine is used as 0, and the best estimate for the average human body temperature is set at 96.
Over time, as the freezing point and boiling point of water at sea level atmospheric pressure proves to be more accurate reference points, the Fahrenheit scale was adjusted to provide exact conversion to Celsius.
Fahrenheit was not an entirely arbitrary choice: it was defined based on two points of reference that could be measured at the time: the freezing temperature of an ammonium chloride brine is used as 0, and the best estimate for the average human body temperature is set at 96.
Over time, as the freezing point and boiling point of water at sea level atmospheric pressure proves to be more accurate reference points, the Fahrenheit scale was adjusted to provide exact conversion to Celsius.
…96? How is 96 a point of reference when you are making a scale from scratch?