Prof Harari emphasizes that most human hierarchies were accidental products of historical circumstance which became solidified and maintained by myths - imagined orders. The most common hierarchy of all - men dominating women - appears to be an exception. Other imagined hierarchies are hierarchies of birth, religion, race and so on - all different with no consistent guiding principles. The patriarchy, however, is present in an overwhelming number of known societies, with variations of degree but rarely true reversals.
He concludes that this probably implies a biological basis, and presents three theories: superior male physical strength, greater male propensity to aggression, and different selective pressure on men and women due to the fact that women have to have the babies. Each theory is found wanting, and he concludes that it is an unsolved problem in gender politics.