 However, the theoretic endeavor of Avempace in his Book of animals seems to be more relevant. Avempace wants to draw a theoretic system embracing all reality. Reality is plenty of forms, and their perfection consists of motion and action (IB-BA: 79). He divides forms into natural and artificial. The specific difference is that natural forms possess a power (quwwa) which moves bodies and by which bodies move themselves while artifacts only move accidentally).