Abstract

We can now approach the interpretation of the famous symbol called the Tetractys or Tetrad, which is a compendium of Pythagorean mysticism. The tetractys is itself a system of numbers. It symbolizes the ‘elements of number,’ which are the elements of all things. It contains the concordant ratios of the musical harmony. It might well be described in the Pythagorean oath as ‘containing the root and fountain of everflowing Nature.’ In one of the acousmata preserved in Iamblichus it is identified with the cosmic harmony. It was also called κσμος, ορανς, πν. Theon says it was held in honour because it contained the nature of the universe.