Axial Age (according to philosopher Karl Jasper). Different cultures, completely geographically separated, witness the flourishing of philosophical-religious movements that promote introspection and promise spiritual transcendence: Taoism, Confucianism, Hinduism, Buddhism, Jainism, Zoroastrianism, Judaism, and classical Greek philosophy. During the Axial Age (8th, 7th, 6th, 5th, and 4th centuries BC), the spread of agriculture allowed for a surplus that enabled this kind of philosophical-religious development. Thanks to 20,000 calories per person in food, fuel, and raw materials, cities and the class of priests/clerics arose.
