One of the topics we didn't really get into on the podcast, and which in our Buddhism reading I actually found the most interesting, is the metaphysics of basic elements of the world.
Nagarjuna argues that reality has no ultimate foundation, and in the episode we discussed that in terms of the possibility of Cartesian "substance" being basic or Spinoza's solution of making God the single, basic substance. But what about atoms, either physical, or logical (as in Russell/Wittgenstein) or something else (as in Leibniz)? In all of these cases, the elements are supposed to be basic, i.e. not defined necessarily in terms of something else; this is what Nagarjuna is arguing against as svabhāva, or substance. Here's what Westerhoff (in the summary section of his book:, p. 203-205, has to say about this:
Another difficulty arising if we assume there are substances is the relationship between such substances and their properties. We cannot just conceive of some substance as an individual instantiating properties. ...Suppose that water-atoms are substances and that their only intrinsic property is wetness. Now what is the individual in which wetness inheres? Since it is not characterized by any other properties, it must be some kind of propertyless bare particular. What makes it a bare particular? Given that we are dealing with substances here, it had better not depend on some other object. But if it is a bare particular by svabhāva and being a bare particular is therefore its intrinsic nature we are in the same situation as we were with the water-atoms and their wetness. For now we can ask what the individual is in which being a bare particular inheres, and then we are well on our way to an infinite regress. Note that this problem does not go away if we feel uneasy about the property “being a bare particular” and do not want to admit it. For we have to assume that the individual has some determinate nature due to which it is a bearer of its properties and the difficulty will just reappear with whatever we take such a nature to be.
It does not help much if we conceive of substances as particularized
properties or tropes instead, for then it is unclear how we can individuate one wetness-trope from another. We cannot differentiate them according to the individuals in which they inhere, because we have just rejected the existence of individuals at the level of substances. We cannot say that this wetness-trope is different from that because they turn up in different samples of water, since the samples of water are just collections of tropes. Of course we could try to tell apart the various trope-substances by the collections in which they occur (or, more precisely, by which other tropes they are related
to via a higher-order compresence-trope). The difficulty for this solution is that it introduces dependence-relations via the back door, for every trope will existentially depend on being connected to just these other tropes via a compresence-trope—we cannot take a trope and “move” it to another collection.
Since we want to conceive of substances as entities that are not existentially dependent on one another, this approach inevitably introduces a certain tension into our system. It thus becomes apparent that once more a conceptual scheme which can be more or less straightforwardly applied to non-substances breaks down once we attempt to analyze the supposedly foundational objects of our world in terms of it.
In other words, if you have substance as metaphysically basic, you have to conceive of this substance as without properties, which makes no sense, and if you have properties as metaphysically basic, then you have to think of them as free floating (not tied to substances), which makes it hard to individuate occurrences of the property (i.e. what would relate the different "greens" floating around?). Wittgenstein's solution the Tractatus was to say that the "fact" connecting a property to a particular was the basic unit, and that the elements connected by such a fact don't even make sense in isolation.