Yesterday, a co-worker and I got into a discussion regarding the origin of the word "grocery", whereupon, I opined that originally a "grocer" was one who received goods in batches of 144 -- 144 of anything being a "gross".
This led to Co-worker wondering how the hell anyone would arbitrarily pick 144 as a standard amount of anything.
I offered my opinion that it was for the same reason that many cultures use a base twelve system -- 12 signs in the Zodiac, 12 inches to the foot, two x 12 hours in a day, five x 12 seconds in a minute, same number of minutes in an hour, so on and so forth -- twelve is the highest number that can be counted to using one hand, and 144 is the highest number that can be counted to using both hands.
The blank look on his face was complete, total and final.
Take your right hand and hold it in front of your face, palm in and fingers spread. Take your right thumb and touch the tip of your right little finger and say "One". Touch the thumb to the tip of the ring finger and say, "Two". Tip of middle finger is "Three", tip of index is "Four".
Now, take your thumb back to your little finger and touch the middle section of the finger -- the part between the two joints -- and say, "Five". Mid-length of the ring finger is "Six"; middle finger is "Seven; and mid-point of your index finger is "Eight".
Everyone knows what to do next -- base section of the little finger is "Nine" all the way to base of your index finger, which is "Twelve".
If you grow up using this method to count things, twelve is a logical, elegant number to base your math on.
Now, let us pretend that you are a Babylonian merchant -- or an Egyptian scribe, or even a London greengrocer -- and you are present someplace where a large amount of thingummies that you own, or are in the process of owning, are being offloaded.
As each thingummy passes you, count on your finger joints as shown above -- and when you get to "Twelve" on your right hand, touch the thumb of your left hand to the tip of your little finger. Start over with your right hand -- and when you again get to "Twelve" on your right hand, your left thumb moves to the tip of your left ring finger.
If you continue this, the highest number of thingummies you'll be able to count before running out of finger joints is going to be twelve twelves. Or one hundred and forty-four.
A "gross" -- one hundred and forty-four -- isn't arbitrary at all. It's simply the highest number you can count to on your fingers.