An Argument From Reason Against Mereological Nihilism

Mereological nihilism is the metaphysical thesis that composite objects do not exist. Formally, letting P denote the parthood relational predicate:

Pxy ↔ x = y.

When combined with materialism (as is often done), mereological nihilism entails that the only things that exist are physical simples (such as, for example, quarks and electrons). What are taken by common sense to be composite objects (sometimes referred to by philosophers as "common objects") are, according to the mereological nihilist, really nothing but various arrangements of these simples. So, for instance, a chair is nothing but a collection of simples arranged chair-wise. Similarly, a rock is nothing but a collection of simples arranged rock-wise. And so on. The reality of metaphysical substances is denied. With that being said, some forms of mereological nihilism are less radical than others. For example, the metaphysician Peter van Inwagen holds to a restricted form of mereological nihilism that allows for the existence of composite living things (e.g., plants, animals, and humans), while holding everything else to be nothing but arrangements of simples.

In this post, I want to focus on the most extreme form of mereological nihilism: the thesis that there are no composite objects whatsoever, be they living or otherwise. I also will be assuming strict materialism (i.e., to be is to be physical). I shall argue that mereological nihilism thus understood—what we might call strong materialist mereological nihilism—is incompatible with the reality of rationality and valid logical inference.

A Protestant Parody of Catholic Presuppositionalism?

In the previous post, I laid out an argument against the Protestant doctrine of sola Scriptura as follows (I have added steps 9 and 10 for the purposes of this post):

1. If a collection of books is fallible, then it can be the case that something that one of the books in the collection teaches is wrong (since at least one of the books could be fallible).
2. If a collection of books is a collection of infallible books, then all of the books in the collection are infallible.
3. If a book is infallible, then it cannot be the case that something it teaches is wrong.
4. Therefore, if a collection of books is a collection of infallible books, then all of the books in the collection are such that it cannot be the case that something that one of the books in the collection teaches is wrong (2, 3).
5. Therefore, if a collection of books is a collection of infallible books, then it is not the case that the collection of books is fallible (1, 4).
6. Assume for reductio that Sacred Scripture is a fallible collection of infallible books.
7. Then, Sacred Scripture is not a fallible collection of infallible books (5, 6).
8. Contradiction (6, 7). Therefore, Sacred Scripture is not a fallible collection of infallible books.
9. If the doctrine of sola Scriptura is true, then Sacred Scripture is a fallible collection of infallible books.
10. Therefore, the doctrine of sola Scriptura is false (8, 9).

The justification for (9) is that given that the canon of Scripture is not taught in Scripture and given that sola Scriptura maintains that Scripture is the sole infallible authority, it follows that the canon (since we know of it by a source other than Scripture) is known only fallibly. But then since the canon specifies the collection of books that belong in Scripture, Scripture becomes—epistemologically speaking—a fallible collection of infallible books. The other premises essentially just unpack the concept of a fallible collection of infallible books.

This argument seems rather devastating for the Protestant doctrine of sola Scriptura. But consider the following parody argument that a Protestant could construct against the Catholic doctrine of an infallible Magisterium: