10/Historical Note
Historical Note on $10$ (Ten)
Aristotle made the obvious statement that $10$ is the usual number base because we have $10$ fingers. This view was echoed by the Roman poet Ovid.
It is noted that not all cultures use $10$ -- some use $5$ (based on the number of fingers on a single hand) and some use $20$ (based on the total number of fingers and toes).
The number $10$ was considered holy by the Pythagoreans, who set great score to the fact that $10 = 1 + 2 + 3 + 4$.
They knew about $8$ celestial bodies:
and also believed in the Central Fire.
In order to satisfy their belief that $10$ was such a special number, they hypothesized the existence of a Counter-Earth which orbited the Central Fire in such a position as to be hidden from us by the Sun.
The number $10$ is expressed in Roman numerals as $\mathrm X$.
It has been suggested that this originates from:
- joining up two $\mathrm V$s, each representing $2$ hands held up showing the full $5$ fingers
or:
- an abbreviation for $10$ tally marks, with a line struck through them to indicate that $10$ had been reached.
Also see
Sources
- 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $10$
- 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $50$
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $10$
- 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $50$
- 2008: Ian Stewart: Taming the Infinite ... (previous) ... (next): Chapter $2$: The Logic of Shape: Pythagoras