Associated with this there is the question of the mysticism of number. This is the idea of rhythm. Every movement must have its rhythm. There cannot be movement without rhythm. By rhythm we imagine the intervals of time, such as hour or minute, or in music crochet, quaver, semibreve. All these arise from our habit of dividing time into rhythm. We do this because our life itself depends on rhythm. The beating of the pulse, of the heart, in the head - all show life's rhythm.