5. After secular instruction in Grammar, Poetry and History, and after religious education and doctrine, philosophic study should begin with the mathematical branches. Here everything is set forth in Neo-Pythagorean and Indian fashion. Not only numbers but even the letters of the alphabet are employed in childish trifling. It was particularly convenient for the Brethren that the number of letters in the Arabic alphabet is 28, or 4 multiplied by 7. Instead of proceeding according to practical and real points of view, they give the rein to fancy in all the sciences, in accordance with grammatical analogies and relations of numbers. Their Arithmetic does not investigate Number as such, but rather its significance. No search is made for any more suitable mode of expressing number in the case of phenomena; but things are themselves explained in accordance with the system of numbers. The Theory of number is Divine wisdom, and is above Things, for things are only formed after the pattern of numbers. The absolute principle of all existence and thought is the number One. The science of number, therefore, is found at the beginning, middle, and end of all philosophy. Geometry, with its figures addressing the eye, serves merely to make it more easily understood by beginners, but Arithmetic alone is true and pure science. And yet Geometry too is divided into a sensible form of it which deals with lines, surfaces and solids, and a pure or spiritual form which treats of the dimensions or properties of things, such as length, breadth and depth. The object both of Arithmetic and Geometry is to conduct the soul from the sensible to the spiritual.