I have spent a good deal of time criticizing the idea of a “perennial philosophy”, the idea (expressed by Ken Wilber and others before him) that the great sages of the world have always basically agreed on the really important things. In the past I had said there were perennial questions but with different answers; now I’m not even sure whether that is the case.
And yet I am struck by a particular phenomenon from which the perennialists draw a great deal of inspiration – and that is the pervasive influence of nondualism. “Nondual” is a literal English translation of the Sanskrit a-dvaita, the name of Śaṅkara’s school of Vedānta philosophy. But the core idea of nondualism has been asserted by a very wide range of philosophers around the world – from people who could never have heard of Śaṅkara, to Śaṅkara’s enemies.
That core idea is that the truest, most ultimate reality should not be identified with the many plural distinct things we typically observe and the distinctions between them. Rather the true reality is ultimately one, or at least (a literal translation again) not two, and not more than two either. That ultimate is often (not always) spoken of as ineffable, beyond words, so that to the extent that one can speak of it at all one must speak of what it is not (the famous neti neti of the Bṛhadāranyaka Upaniṣad. But the most important thing that the ultimate is not, is dual or plural. It might not be one exactly, but it is closer to being one (or perhaps zero!) than it is to being two or more.
And the two that it really isn’t, is the distinction of subject and object. Nondualists tell us that we are misled by that core grammatical distinction of the Indo-European languages (languages which many, but not all, of those nondualists speak). Ultimately “you are that”: the distinction between our supposed individual consciousness on one hand, and reality on the other, must collapse.
That is nondualism in a nutshell. And while Śaṅkara was perhaps nondualism’s purest and most famous exponent, it was taken up by many others in various ways – including by very different enemies of Śaṅkara. The later theistic thinker Rāmānuja wanted to assert against Śaṅkara that the plurality of things in the world is real, and yet he accepted Śaṅkara’s basic nondualism: his philosophical system was called Viśiṣṭādvaita, differentiated or qualified nondualism. He aimed to produce a harmonious synthesis: the plurality of the world is not an illusion, as Śaṅkara would have it, but the parts of the divine One.
Now while Rāmānuja could be harshly critical of Śaṅkara himself, he remained in Śaṅkara’s basic camp of loyalty to the Vedas and especially the Upaniṣads. Śaṅkara had much greater hostility to the Buddhists, who rejected the entirety of the Vedas and Upaniṣads. And yet – here is the striking thing – a very large number of Buddhists themselves accepted nondualism. The Yogācāra school had been taking up some form of nondualism since before Śaṅkara’s time, enough that to other Vedāntic thinkers Śaṅkara’s school just looked like the Buddhism they were familiar with; for that reason they even called him a “crypto-Buddhist” (pracchanna bauddha). By Śaṅkara’s time a great deal of Indian Buddhism had itself become nondual – and that Buddhism in turn reached its full flower in East Asia, where it became the dominant form of Buddhism. Thus John Dunne uses the term nondual to refer to the present-centred, nonjudgemental meditation traditions created by these newer sorts of Buddhisms, Yogācāra and beyond. (Ron Purser rightly pointed out, though, that it is harder to see anything “nondual” about the modern mindfulness practices that take up those meditation traditions.)
I often find reading East Asian Buddhism weird because it looks to me so much like the Advaita Vedānta that arose in opposition to Buddhism. But opposed or no, these nominally opposed sides – Buddhists and Vedāntins – could agree on a basic nondual worldview. By the 20th century, the Japanese Buddhist philosopher Nishida Kitarō could proclaim constructively, in his own voice, that “Ātman and Brahman are identical.” (An Inquiry into the Good p. 80) For Nishida it made sense to have a Buddhism that actually took up the Upaniṣads’ worldview.
Centuries before Śaṅkara, in Rome and in Alexandria – the West – a Greek-speaking follower of Plato, named Plotinus, had proclaimed that everything is an emanation from what he called “the One”. Now that’s not quite nondualism per se, because everything comes from the One; it is not identical to it. Centuries later, the pious Shaykh Ahmad Sirhindī would insist on that distinction as crucial (“not ‘all is Him’, but ‘all is from Him’.”)
But in between Plotinus and Sirhindī, a significant number of Sufi Muslim thinkers, influenced by Plato and Plotinus, had indeed proclaimed the oneness of everything – while having relatively little contact with the South or East Asian worlds. For them, it’s not just that we come from God, but at some level we indeed are God. Perhaps most notorious of these was al-Hallaj, executed for proclaiming the nondifference between God and a self fully understood. Later ibn ‘Arabī became perhaps the most influential Muslim philosopher in the world by proclaiming the unity of all existence (wahdat al-wujūd). Ibn ‘Arabī’s thought found a natural home in India, and indeed the Mughal philosopher-prince Dara Shukoh sought to create a merged philosophy that blended ibn ‘Ārabī with the Upaniṣads. (It was that very Muslim nondualism that Dara’s contemporary Sirhindī felt the need to write against.)
Nondualism may well be the single most popular philosophical theory in human history. I’m not sure I can think of any other major philosophical idea that flowered so much in so many different places, more or less independently. I think that gives us prima facie reason to think the nondualists were on to something important. In that, at least, I am cautiously with the perennialists. But the perennialists typically take this too far, in that they tend to assume that this nondualism must have come out of mystical experiences. It’s not an unreasonable assumption, in that mystical experience often involves a perceived transcendence of subject-object distinction. But it is crucial that most of the thinkers I’ve named here do not cite experience as the ground of their claims. Wilhelm Halbfass in India and Europe reminds us that Śaṅkara never refers to any experiences of his own; Chinese nondualists like Zhiyi didn’t either, according to John McRae and Robert Sharf. But if anything, I think that nondualism’s non-experiential provenance gives it more plausibility. That is, nondualism’s exponents did not merely see it in an altered state of consciousness, but viewed it as somehow a logical necessity.