Incas Used Binary?

Abhijeet Chavan writes "An article in the Independent reports that a leading scholar believes the Incas may have used a form of binary code 500 years before computers were invented. 'Gary Urton, professor of anthropology at Harvard University, has re-analysed the complicated knotted strings of the Inca - decorative objects called khipu - and found they contain a seven-bit binary code capable of conveying more than 1,500 separate units of information...If Professor Urton is right, it means the Inca not only invented a form of binary code more than 500 years before the invention of the computer, but they used it as part of the only three-dimensional written language.'"

Comments

Not 1500 units of information

[p3d0]

After multiplying the different permutations of the knots, they reach the conclusion that there are 1536 possibilities, and then go on to state that "This could mean the code used by the makers allowed them to convey some 1,536 separate units of information".

That is a poor interpretation. 1536 possibilities allows someone to encode 10.6 bits of information. To encode 1536 "separate units" of information, each unit must represent no more than 1/145th of a bit. That is a very, very small amount of information, equivalent to having someone tell you something you were already 99.5% sure was true, such as "wow, this poker hand is not a straight!" or "guess what, my birthday this year does not fall on Friday the 13th".

It may be closer to the truth to say their knot language had 1536 different symbols, as compared with the 50-or-so letters, numbers, and punctuation marks we use in English.