The fourth part includes a commentary on the theory of evolution,[29][30] the origin of the universe,[31] the difference between man and animal, the origin of man, the difference between the soul, mind, and spirit,[32] human nature,[33] the origin of the spirit and mind of man, the relationship between the spirit and the body, the relationship between God and man (emanationism),[34] the physical and intellectual powers of man, the differences of character in men,[33] the degree of knowledge man possesses and the knowledge the Manifestations of God possess, man's knowledge of God, the immortality of the spirit, the state and progress of the spirit after death,[32] fate,[7] the influence of the stars,[35] free will,[36] visions, dreams[37] and communication with spirits,[38] and spiritual and physical healing.[39]