Recently I’ve been working on a paper about the fundamental level of reality, and I’ve just about got a draft of the paper ready now. It’s still quite rough and sketchy, but since I need some time away from it before it’s beneficial to have a fresh look, I might as well post about it here. The full paper is available here. A word of warning: although I discuss philosophical themes such as the ‘levels’ metaphor and how it is related to ontological dependence, there is also quite a lot of physics in the paper. I developed some examples from physics that I’ve used before, especially regarding the Pauli Exclusion Principle, and there is also some discussion about fundamental physical constants, especially the fine structure constant. I also use the GRW theory of quantum mechanics as well as loop quantum gravity in my examples. I quite enjoyed browsing physics journals when I did my research for this paper, but I have to admit that I have no deep understanding of the underlying mathematics and there may very well be serious confusions in my examples. Hence, I would especially welcome any input from those who do know their maths/physics.

I’m interested in three question in the paper:

1. Is there a fundamental level of reality?
2. If there is, how can we know that this is the case?
3. Can we know what this fundamental level is like?

I defend a positive answer in regard to the first question, but I am perhaps more interested in the second, methodological question, as well as the third question which is closely related to the second. The presentation of the paper follows the discussion familiar from Every Thing Must Go (2007) by Ladyman & Ross. Ladyman & Ross argue that reality is not organised into levels in the first place and that there is no fundamental level (pp. 4, 53–7, 178–80). I attempt to show that there are plausible interpretations of the ‘levels’ metaphor. The interpretation that I prefer is in terms of ontological dependence. I also present an argument for a fundamental level (outlined below) and a detailed analysis of each premise of the argument. The argument is a priori in nature, although potential support from current physics will be discussed in detail. If the argument is correct, it shows that a fundamental level is metaphysically necessary for the existence of macrophysical objects, but I will not offer support for such a strong result. Rather, in the process of defending the premises of the argument, it will be suggested that a fundamental level is physically necessary, that is, necessary given the physics of the actual world, albeit only if certain emerging theories in physics are correct. At the very least, I hope to establish that a fundamental level of reality is a viable metaphysical possibility. I also analyse our means to acquire information about the existence and nature of this level.

Here is a brief outline of my main argument:

1. There are macrophysical objects.
2. Certain things are physically necessary for the existence of macrophysical objects, e.g. the laws that govern molecular binding.
3. These laws require certain regularities on the microphysical level, e.g. that fundamental physical constants fall within a specific range.
4. The required regularity of the microphysical level would not be possible without a fundamental supervenience base.
5. Therefore, there is a fundamental level.

I will not go into the details of the premises here, you can see the actual paper for that. In any case, I hope that the first premise needs no further support, but I defend each of the remaining premises. It should be noted that the modality in premise 4 can be interpreted either as metaphysical or physical. I am optimistic about the metaphysical interpretation, but I will focus on the weaker, physical reading. So, we are primarily interested in the existence conditions of macrophysical objects given the actual laws of physics. I’ll conclude this post with a passage from a paper on braided ribbon networks related to loop quantum gravity, entitled ‘Locality and Translations in Braided Ribbon Networks‘, by Jonathan Hackett, as it supports my case quite nicely:

In the last century, there have been repeated discoveries of underlying structure. Moving from macroscopic objects, to atoms, to components of the nuclei, to quarks, it has been demonstrated repeatedly that the differences between supposedly fundamental particles are, in fact, merely consequences of the composite structure of underlying reality. It only seems a natural progression that such an approach of looking for underlying structure be used to explain the particles of the standard model. Attempts towards this end, dubbed preon models, met with many obstacles, but still there was something deeper that presented itself as a difficulty. The difficulty is that, as such a process does not have an end, we can continue to suppose that below the currently understood structure is another set of more fundamental particles. This idea quickly becomes unappealing at a philosophical level, or even a practical level, as the question then becomes ‘What could make it end?’. The idea that the preons would be as fundamental as possible [...] provides a way of achieving the desired end. One way to achieve this end is to suggest that the preons be composed of structure within spacetime. (Hackett 2008: 5757.)