Sacred Number

In chapter 2 the seven traditional arts (aka Liberal Arts) are introduced. These existed in medieval times and were in some way descended from the original arts of Sacred Number responsible for the ancient model of the size of the Earth and the monuments that made reference to this model through their dimensions.

Three of these "arts" are explicitly numerical, involving

1. a knowledge of Number (often called arithmetic but more concerned with the properties of number)
2. a knowledge of Harmony, seen in music but available within harmonious proportions
3. a knowledge of Geometry, especially the properties of geometrical forms in transforming number

Three of the arts were linguistic, being called the Trivium from which our word trivial derives, to be mastered before studying the greater, numerical arts or Quadrivium. They involved,

1. Grammar, the structure of language itself
   
2. Dialectic, logic and the analysis and comparison of arguments
   
3. Rhetoric, the stating of arguments or, more likely this was Poetry
   

The seventh art was of Astronomy, sometimes called the royal art. We show in Sacred Number and the Origins of Civilization (Chapter One) that Astronomy is the likely teacher of the domain of number itself to ancient peoples. However, it became clear that there must have been other traditional arts, since three more emerge as essential:

1. Mythology, which lay at the heart of the oral traditions before the widespread use of writing
2. Metrology, which was used within monuments and was derived from the size of the Earth
3. Cosmology, which makes up the world views found in all religious thought and also within modern science

This creates a list of arts at least ten long. I created a graphic to illustrate this before other important ideas came along at the end of Sacred Number:

 They are organised here as a Tetractys - one systematic way of organizing ten elements. Metrology is here put in the centre but the arrangement is not the only interesting one.  Astronomy has gained two partners, Mythology and Cosmology, that are all "whole grasping", that is holistic arts used to build the ancient worldview. They form a triple with the numerical and linguistic arts in the other two corners, with metrology then forming the tenth art, in the middle and between, like the Pole itself.