Defenders of cross-cultural mystical experience are right to note that in many widely varying cultures, respected sages have referred to the experience of an ultimate nonduality: a perception that everything, including oneself, is ultimately one. But one might also then rightly ask: which ultimate nonduality?

Nondualism may be the world’s most widespread philosophy, but it can mean different things – not merely different things in different places, but different things in the same place. Members of the Indian Vedānta tradition frequently proclaimed that everything is “one, without a second”, in the words of the Upaniṣads they followed. But they disagreed as to what that meant. Śaṅkara founded the Advaita Vedānta tradition – a-dvaita literally meaning non-dual – which argued that only the one, ultimate truth (sat, braḥman) was real, and all multiplicity and plurality was an illusion. His opponent Rāmānuja agreed that everything is “one, without a second” – but in his Viśiṣṭādvaita (qualified nondual) school, that meant something quite different. All the many things and people we see around us – what Chinese metaphysicians called the “ten thousand things” – are parts of that ultimate one, and they are real, not illusory.

I was reminded of this point in the great comments on my previous post about cross-cultural mysticism. I had cited W.T. Stace as an influential advocate of the view that mysticism is cross-cultural, and noted how Robert Forman’s book defended Stace by pointing to contentless experiences of void, from the Yoga Sūtras to Hasidism, that “blot out” sense perception. Seth Segall made the important point that in Stace’s own work not all mystical experiences are contentless in this way. Leaving aside the “hot” or “visionary” experiences (like St. Teresa and the angel) which Stace does not count as mystical experiences – even among what Stace counts as genuine mystical experiences, he makes a key distinction between introvertive and extrovertive mystical experiences. This isn’t just a distinction between the interpretations applied to the experiences, but between the experiences themselves. The contentless “Pure Consciousness Events” described in Forman’s book, where distinctions fade into void, are introvertive; experiences of merging with a unified natural world, like Teresa saying “it was granted to me in one instant how all things are seen and contained in God”, are extrovertive.

And here’s where I find this all really interesting: that introvertive/extrovertive distinction, between different types of experiences, corresponds to the metaphysical difference between Śaṅkara and Rāmānuja! Neither Śaṅkara nor Rāmānuja cites experience, mystical or otherwise, as the source of their philosophy. Both claim to be deriving it from the Upaniṣads (and other texts like the Bhagavad Gītā), and they each defend their view (of the scriptures and of reality) with logical arguments. Yet even so, the distinction Stace observed in descriptions of mystical experiences turns out to correspond pretty closely to the distinction between their philosophies.

In Śaṅkara’s philosophy, as in an introvertive experience, the many things of the world, including oneself, all fall away; what remains is the one reality alone. In Rāmānuja’s philosophy, as in an extrovertive experience, the things of the world, including oneself, remain, but they are all unified together: they continue to have a real existence, but as connected members of a larger unity.

All this is a major caveat for perennialist-leaning ideas: even if you were to argue that mystical experience pointed to a cross-culturally recognized nondualism, you would still have to specify which nondualism. The smartass response is to say “all the nondualisms are one”, but that’s not really satisfactory, not even to the nondualists themselves. Rāmānuja attacked Śaṅkara’s view, and while Śaṅkara lived centuries before Rāmānuja, he attacked other thinkers who had views like Rāmānuja’s.

Some mystically inclined thinkers take a moderate or intermediate position that compromises between an absolute nondual view and the view of common sense or received tradition. Such was the approach of Shaykh Ahmad Sirhindī, the Indian Sufi who reconciled Sufi experiences of mystical oneness with Qur’anic orthodoxy by proclaiming “not ‘All is Him’ but ‘All is from Him'”. It’s tempting to view Rāmānuja’s approach to Śaṅkara as similar, tempering an absolute mysticism with a common-sense view of the world as real: Śaṅkara’s mystical excesses take him way out there and Rāmānuja pulls him back. But such an approach doesn’t really work. It’s flummoxed not only by the fact that Śaṅkara claimed no mystical grounding for his philosophy, but also by the existence of extrovertive mysticism: the many who have felt an experience of oneness with the grass and trees would not have been drawn by that experience to Śaṅkara’s view, but directly to Rāmānuja’s. (I have previously suggested that Rāmānuja is indeed moderating Śaṅkara’s overall approach – but with respect to Śaṅkara’s possible autism rather than to mysticism.)

None of this is intended as a refutation of mystical views of reality, or even necessarily of perennialism. It seems to me that both introvertive and extrovertive experiences are found across a wide range of cultures, often accompanied by a sense of certainty, and are worth taking seriously for that reason. But we then need to take both seriously: if the world is one, then are our many differing perceptions illusory or real? Here, I think, it helps that both illusionist and realist forms of nondual philosophy – experientially based or otherwise – also occur in multiple places. The debates between them might help us sort out what reality – if any – the experiences are pointing to.

Cross-posted at the Indian Philosophy Blog.