Why the Number 12?

Every wonder why the number 12 is seen in so many publications and lectures?  Here are just a few where the number 12 is used.

• 12 apostles in Christianity (Judaism and Islam have similar)
• 12 as the amount in a dozen
• 12 hours in a day and subsequently 12 hours in a night
• 12 months in a year
• 12 inches in a Foot of measurement
• 12 is dividable by 60 making for the clock 5, 10, 15, 20, etc increments
• 12 functions keys on computer keyboards
• 12 keys on all standard telephones (1 through 9, 0, * and #)
• 12 ounces in a pound
• 12 people have walked on the moon
• 12 is a super perfect composite number (divisible by 1,2,3,4,6,12)

As you can see there are serious considerations to be had when thinking about the number 12.  So, where did it come from?  After all we have 10 fingers and 10 toes.  You would figure that 10 would be replete in religion, time keeping and in art.

The ancient Egyptians divided up the day by 12 Horus and 12 Sets.  Horus would do battle with Set for the night.  So, why was 12 used and not 10.

The answer came to me while playing guitar.  There are 12 notes not including the octave.  So, I think that music as the deciding factor in this fascination with the number 12.  Also, there are other tunings that do not use 12 tonal notes, like the Sitar.  However, if you look at all Guitar Fret Boards, they are logarithmic and are equally spaces. (Log rhythmically of course)

Classical Guitar

So, next time you see a Guitar or think of why there are 5, 10, 15 minutes on the circular clock or why there are 12 hours in the day and 12 at night.  Where did this number really come from?

However, this is not the most incredible finding I have found.  When going to the Octave of a 12 tonal standard Guitar there is the number 13 which has to be considered.  At the same time it sounds just like the first note in the Octave yet it is not part of the 12 notes.  So, the question is, "Is the Octave an odd note out?  Or is it a yin and yang thing where mysterious fill one's head."