Irreconcilable opposites exist side by side in human nature. Vohu Manah, the Good Mind, and Aka Manah, the Evil Mind, are the two principles poised against each other in man. Vohu Manah with his good thoughts and Aka Manah with his evil thoughts are wrestling within man. The clinging creeper of evil has wound itself around the tree of goodness and chokes its life. Struggle is the fundamental fact of man's life.
Man is a human being and an animal, a civilized man and a savage, an angel and a demon in one.
Every human being carries his Angra Mainyu in his heart. Life is a long battle. Man has to fight evil within himself and in the world without. He has to seek the enemy, shake his fist at him, wage war with him, bravely face his attacks, intrepidly risk his all and subdue the evil in his nature. Life is neither all gaiety, nor all gloom.