In his 1953 work The Origin and Goal of History, Karl Jaspers created one of the more enduring concepts in the study of cross-cultural philosophy: the Axial Age (Achsenzeit). With this concept, Jaspers was pointing to the stunning outpouring of human creativity between 800 and 200 BCE. This was the era of ancient Greek philosophy from the pre-Socratics to the Hellenistic schools; of the Upaniṣads, the Buddha and Mahāvīra in India; and of the great Warring States philosophers in China (Confucius, Laozi, Zhuangzi, Mencius, Mozi, Xunzi, Han Feizi), to whom nearly all discussions of Chinese philosophy return. Somewhat more controversially, Jaspers identified it as the age of Zoroaster and most of the Hebrew prophets.

The arising of the Axial Age is all the more striking because it would appear to be coincidence. Thomas McEvilley in The Shape of Ancient Thought tries to portray a connected world of Greece, India and the Middle East where ideas flowed freely, but most of his evidence is shaky conjecture. Moreover, even if one were to accept his thesis, there is no connection of these civilizations to China until quite late in this period, well after the flourishing of Warring States philosophy. So at least some of it appears indeed to be coincidence.

What has been striking me recently, however, is something that Jaspers and others did not seem to notice: there seems to have been a second Axial Age. By this I do not mean the occasional claims now made that our present age today is a second Axial Age. Rather, I’m referring to a second age in human history a few hundred years after the first one, one that historians of philosophy have largely tended to neglect – an age where the ideas generated in the first age took the form in which we now know them.

This second Axial Age, I would argue, happened mostly between about 200 and 600 CE, with a few outliers beyond the main time (as is the case with the first age). In China these centuries are the age of Wang Bi and Guo Xiang, the Daoist commentators who put together the Laozi and Zhuangzi as we know them today. In India they are the time of Buddhaghosa putting together what we now call the Pali Canon. In the West, now that the cultural centre has shifted from Greece to Rome, we get the works of the Stoic and Skeptic thinkers whose full works survive – Marcus Aurelius, Sextus Empiricus – where from their predecessors Zeno and Pyrrho we have only fragments. Platonism is developed into Neoplatonism. So too, of course, we get Augustine putting together a comprehensive Christian philosophy, along with the collection of the New Testament itself.

I mentioned the idea of a second Axial Age to sinologist friends, who pointed out that the second age shapes our idea of the first; we imagine the ideas of the first Axial Age as they were redacted in the second. So that it is an age of assessment and sorting through the past. (In China, they noted, the thinkers of the first age claim merely to be representing the past, as the thinkers of the second age do, but we tend to believe the thinkers of the second age on this claim and not those of the first. Perhaps that is because we are used to the Western and Indian thinkers of the first age, who often seem comfortable with the fact that they are innovating.)

Exceptions to the second age are real and notable – Andronicus of Rhodes, who collected Aristotle’s works into their present form, and Lucretius the Epicurean both fit this pattern in Rome as early as the first century BCE. But one may also notes the exception from the first age: most notably Jesus himself, at least as historically significant an innovator as anyone in that age, but well after it. Nāgārjuna and the Mahāyāna movement also seem to be creativity of the sort attributed to the first age, occurring in these middle years. The idea of the Axial Age as I understand it is to speak of a general pattern, and it seems to me that if we can speak of such a pattern in the first age we can speak of it in the second. One might well be suspicious of the idea of the Second Axial Age, but such suspicion would also seem to apply to the first.

If one does accept the idea of a second Axial Age, what might it then mean? Unlike with the first age, we do not have to chalk any of it up to coincidence. For one thing, by this point there had been actual contact – Alexander’s conquests in South Asia, Buddhists in East Asia – that could have cross-fertilized the traditions. But one might also suggest an internal logic to this development: that the new traditions of the first age were of a sort that took a few hundred years to get established, given the conservative nature of the age’s societies. So only by this later age were these traditions ready to take root as more widely established traditions, which could then be systematized.