Numbers. Muslim scholars agreed with the ancient Greek notion that mathematics is the underlying foundation of all knowledge. They knew that studying mathematics gives one skill in logic and reasoning. Furthermore, one of the main foundations of Islam is the concept of Tawhid (Oneness) of the whole interconnected world, and Muslims viewed mathematics as a way to make sense of the physical world and its union with the spiritual world. This link between the science of numbers and understanding of the divine reality was so critical to early Muslim scholars that they referred to mathematics as "the tongue which speaks of Unity and Transcendence." Their affinity for mathematics as spiritual symbolism is apparent in Muslim art and architecture, which often includes the number 1, or a single, central design element, to remind the viewer that there is only one God. Hence, the number 1 is...