There are two principal reasons for this. One is the speed of vibrations, the other is the direction that a certain action takes. In order to make this comprehensible one may divide the speed of vibrations into three stages: slow, moderate, and quick, or as they are called in Sanskrit: Satva, Rajas, and Tamas. The first stage is creative in its effect, the second stage is progressive, and the third stage is destructive. This gives us the reason for death and decay and destruction: every living being and every object decays or dies when it strikes that particular speed which is destructive. Besides, as every object looks different when seen from different angles, so every creative force manifests differently when it takes different directions. This explains why a person's right hand is stronger than his left, with few exceptions; and why the right leg is always inclined to go forward first and not the left leg.