This is a summary of Johnathan Schaffer’s “Is there a fundamental level?”

Schaffer argues that there are no good a priori arguments or a posteriori evidence for fundamental particles. (I won’t go over his arguments here.) The replacement of quantum electrodynamics with quantum field theory puts the idea of fundamental particles into doubt. Consequently, we should be agnostic about whether a complete microphysics will postulate fundamental particles.

Indeed, considerations of renormalization in quantum field theory have led physicist Howard Georgi to suggest that effective quantum field theories might form an infinite tower which “goes down to arbitrary short distances in a kind of infinite regression … just a series of layers without end” (p. 505).

Fundamentalists in metaphysics make three claims:

- Nature is stratified into levels
- Nature has a fundamental level.
- The entities at the fundamental level are real (mereological atomism), while the other entities are derivative.

Schaffer examines problems for physicalism, epiphenomenalism, and atomism if they reject fundamentalism. For physicalists, the final microphysical theory describes the fundamental level of reality on which all else supervenes. For epiphenomenalists, all causal powers inhere at the fundamental level. For atomist, there are only fundamental entities and no macroentities.

**Problems for Physicalism: **There are various formulations of physicalism, but they all contain the core idea that physics serves as the base, and that the mental etc., is derivative. If atomism is false and there is an infinite descent, a dilemma arises for the physicalist in identifying the physical base. There are two horns:

- Suppose the physical base is found at some finite number of levels. That means that there will lower level entities that are not composed of, supervenient upon, realized by, and governed by, the physical base. In other words, the base will not be the base for everything as physicalism requires.
- Suppose the physical base is found infinitely below a certain cut-off L. L is redundant to the base because all the entities in L are composed of, supervenient upon, realized by, and governed by, L-1. Similarly, L-1 is redundant because of L-2, ad infinitum. What follows is that any L will be a true-but-redundant base. It will be true-but-redundant that everything is nothing over and above the subatomic, or the chemical, or the psychological. There will be no interesting ontological difference between quarks and qualia. Without a fundamental level, there is nothing to distinguish what is primary from what is derivative.

**Problems for Epiphenomenalism: **Schaffer gives the epiphenomenalist argument (p. 508):

- Distinctness: the higher level entities are distinct from their lower level composers/subveners/realizers/governers.
- Micropower: the lower level entites are causally potent.
- Exclusion: it is not the case that both the higher and lower level entities are causally potent.
- Epiphenomenalism: the higher level entities are causally impotent.

Similar problems occur for the epiphenomenalist. If the causal powers are at some level L, those powers will be drained by L-1, ad infinitum. The causal powers would “drain away down a bottomless pit.”

**Problems for Atomism: **On atomism there are no composite macroentities but only fundamental entities in various arrangements. If there is an infinite descent, then “all entities would dissolve into thin air.”

Given the dependence of physicalism, epiphenomenalism, and atomism on fundamentalism, agnosticism about fundamentality entails agnosticism about physicalism, epiphenomenalism, and atomism.

An alternative to fundamentalism is to say that even if there are no mereological atoms, there may be a fundamental supervenience base. Supervenience-only fundamentality is the disjunctive view that there is either a fundamental level of nature or an infinitely boring descent. In a boring descent, the properties of the parts supervene on the properties of the wholes. Supervenience-only fundamentalism is compatible with physicalism: the physicalist can use the supervenience base to distinguish the primary from the derivative. Supervenience-only fundamentalism is not compatible with epiphenomenalism, because, on the infinitely boring descent, the boring parts and their wholes supervene on each other, which means both would be fighting for the locus of causal power. Supervenience-only fundamentalism is not compatible with atomism, because the entities in the base could be composite.

In conclusion, there are at least three metaphysical pictures:

- Full-blown fundamentality: a complete microphysics would reveal fundamental particles
- Supervenience-only fundamentality: there exists a complete, finite microphysics.
- Full-blown infinite descent: there does not exist a complete, finite microphysics. One way to view a metaphysic of infinite descent is to say that no level is privileged. Quarks, chairs, and minds would be ontologically equal. There is no locus of causal powers; instead, causation is at every level.

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Schaffer, Johnathan. Is there a fundamental level?