Morris refers to “advantages of backwardness” when describing how weaker or more peripheral areas can enjoy greater developments in social and technological areas by building on the knowledge and technology gained from stronger, more advanced societies. An example of this is how the West eventually managed to overtake the East after a long period in which the East had been more technologically sophisticated.

A term coined by the German philosopher Karl Jaspers, the Axial Age refers to the period from the 8th century to the 3rd century CE when numerous influential religious and philosophical leaders and texts appeared across Eurasia, such as Zoroaster in Iran, the Hebrew Bible, Socrates and Plato in Greece, Buddha in India, and Laozi and Confucius in China. Morris holds up the Axial Age as an example of shared, common reactions to social development across societies, arguing that the Axial Age was a response to strong centralized high-tier states.

Cores are regions where social development was highest in Morris’s theory of history. For example, ancient Egypt and the city of Ur are cores.