According to the standpoint of the Sufi both are right and yet both are wrong, for the Sufi applies the law of vibration to his understanding of the world: each note has its finish at the octave, and so there are an ascending and a descending scale. Each strong accent in anything has its weak part to balance it. The sun rises as well as sets, the new moon develops to the full and wanes until it is new again. Each wave of the sea which rises high is drawn back; each helpless child is helpless again when old. This is the nature of evolution.