One (1)

One ("the Monad") is the atomic building block of natural numbers, and as such, the simplest natural number. The unary numeral systems build numbers from a single symbol representing the monad.

Many philosophical systems emphasize the Unity (oneness) of the Ultimate Principle. This is sometimes related to the idea of zero complexity. When one bit of information is introduced to the Ultimate Principle, it splits in two, producing the first duality - yin and yang.