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Would Aliens Use Base 10?

Date: 05/13/2002 at 06:31:08
From: Christopher Walsh
Subject: would aliens count in 10s?

If aliens had 6 fingers, would they count in 12s? ...would their 
"decimals" be in 12s?

I think that our number system (10... 20... 30... etc.) is 
connected to our digits and is not necessarily the only way of 
doing it. It is not arbitrary as such, but could just as easily 
be any other number. All you would have to do is put another 
couple of numbers in the series.

A friend thinks that 10 is the only way of doing it. I 
disagree. Could you decide the argument for us?


Date: 05/13/2002 at 08:06:59
From: Doctor Jerry
Subject: Re: would aliens count in 10s?

Hi Christopher,

I can't decide the argument for you - all I can do is to give my 
opinion and cite some checkable facts.

First, I think it highly likely that if aliens had six fingers on 
each of two hands, then their number system would be base 12.

You may know that there are groups in the world in the present 
day who believe that base 12 is better than base 10, because 12 
has more divisors that 10 and so, they argue, the arithmetic 
would be a little easier.  They are called things like the 
"duodecimal society."  See 

The Babylonians used a mixture of base 60 and base 10.  The 
Mayans used base 20.  See, for example, 

Computers use base 2; programmers use base 8 (octal) and base 16 
(hexadecimal) because they are closely related to base 2 and thus 
more convenient.

Our clock is based on base 12 ideas (the 12 or 24 hour thing has 
Babylonian roots).  Note that 12 divides 60 evenly. 

So clearly, base 10 isn't "the only way of doing it." 

- Doctor Jerry, The Math Forum 
Associated Topics:
High School Number Theory
Middle School Number Sense/About Numbers

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