While Buddhist schools have many different takes on metaphysics – on what the world really is – they all acknowledge a distinction between two truths, or two levels of reality. That is: there is a conventional truth, the one familiar to us in everyday life where we can fruitfully speak of individual selves or persons and other everyday objects – and another, more ultimate (paramārtha) truth that is distinguished in some respect from the conventional, truer than the conventional. Their widely varying metaphysics mostly have to do with how we understand the ultimate truth, and I’ll talk about that more next week. I want to start this time, though, I want to note a key point that the metaphysical schools share: the importance of breaking down the conventional – or, put another way, of seeing through it.

Śāntideva’s metaphysical chapter insists on the illusory nature of conventional reality: he compares it to a dream, to the trunk of a banana tree (which is hollow, not actually a “trunk” at all but a pseudostem made out of leaf sheaths). Candrakīrti – a philosopher in the same Madhyamaka school of philosophy as Śāntideva, within a hundred years or so before him – tells us that the real meaning and (Sanskrit) root of the very word for “conventional”, saṃvṛti, is that it obscures and covers up – identifying it with the moha, delusion, that Buddhists generally view as one of our greatest problems.

And it’s that illusory nature that has ethical significance. For crucially, Śāntideva tells us, it is by recognizing the illusory nature of things that we stop being attached to them – a nonattachment that is at the heart of Śāntideva’s worldview.

So, it matters deeply to Śāntideva that the conventional is like a dream, like the trunk of a plantain tree. In order to be liberated from suffering, you have to see through everyday reality – it’s the seeing-through itself that’s the really important thing, rather than what you see through it to. Such a view strikingly bites the bullet that C.S. Lewis shoots at the conclusion of The Abolition of Man:

You cannot go on “seeing through” things for ever. The whole point of seeing through something is to see something through it. It is good that the window should be transparent, because the street or garden beyond it is opaque. How if you saw through the garden too? It is no use trying to “see through” first principles. If you see through everything, then everything is transparent. But a wholly transparent world is an invisible world. To “see through” all things is the same as not to see.

For Madhyamaka Buddhists like Śāntideva at least, the point is in many ways to make the things of the world more invisible – not wholly transparent, perhaps, but transparent enough that you can see through them even when there is nothing behind them to see. For them, contra Lewis, that is the clearest seeing of all. Theravāda thinkers like Buddhaghosa don’t go that far: you can see something when you see through the everyday, the smaller reduced parts. But the two Buddhisms share the point that it is important to see through the everyday world.

In all of this, it’s instructive to compare Buddhism with Platonism – and the Abrahamic or Semitic monotheisms, like Lewis’s, that were all deeply shaped by Plato. In both Buddhism and Platonism, there is a recognition of the unsatisfying nature of the material world. In both, something beyond that world – even if that beyond is constituted solely by paradox or absence – is truly ultimate.

Monotheists disagree on how far they want to go with that Platonism: even within Christian theology, Augustine tends to agree that the unsatisfying world is something to be transcended, while Thomas Aquinas’s natural law does a lot more to affirm the world-as-it-is. Even in Augustine’s Platonism, though, the conventional still points to the ultimate; the conventional or natural world reflects the divine ultimate, partakes in it positively. There are strong elements of the conventional in the ultimate. In Buddhism the conventional just breaks down.

I tried to get at that point before by comparing Śāntideva’s view to the major Muslim theologian ibn Sīnā – ibn Sīnā having been deeply influenced by Plato via Aristotle. The commonality between ibn Sīnā and Śāntideva is in noting that the existing world that we know is incomplete, imperfect, lacking – or it at least it would be without a transcendent God to complete it. The difference between them is just that ibn Sīnā thinks there is such a God, and Śāntideva does not. So for ibn Sīnā, ultimately the existing world is not lacking because it has a God to complete it – whereas for Śāntideva it is ultimately lacking, because it does not.

This, in turn, is why I come to see a deep compatibility between Buddhism and existentialism. Both traditions are atheistic – in a much deeper, more meaningful sense than the know-nothing atheists who think they are only denying one entity. They know that there is no transcendent order reflected in everyday reality. And as far as I can tell, that denial of transcendent order works well with modern science. From Copernicus onward, science came to reveal an indifferent cosmos – which makes a great deal of sense in Buddhist terms!