Book review: The Metaphysics Within Physics

The Metaphysics Within Physics
by Tim Maudlin (2007)

In this collection of essays, philosopher Tim Maudlin makes an extremely strong case against the Humean philosophy of physics.  This position, credited to Hume and popular among contemporary philosophers, posits that the universe is completely described by physical facts about localized quantities at each different place and time.  As Maudlin points out, this doesn’t match current scientific theory or practice.  The state of a system with spatially separated but entangled parts cannot be factored into purely local pieces, and science requires not only facts but also scientific laws.  Laws are not reducible to facts; if they were, they couldn’t do their work of making predictions and answering questions about counterfactual scenarios.  I have in the past distinguished the “Platonic” and “Aristotelian” ways of thinking about laws of nature:  the former speaking of them as having some independent existence, the latter regarding them as being embedded in the natures of existing things.  Maudlin is apparently a “Platonist” in that he takes laws to be completely primitive, but nearly everything he says would also be endorsed by an “Aristotelian” with the suitable reinterpretation of the idea of physical laws.

I take the polemic against the followers of Hume to be the major point of the book, but Maudlin makes several other interesting observations along the way.

He suggests that we are able to assign causality intuitively because the laws of nature approximate a particular “quasi-Newtonian” form in which separable subsystems each have their own “inertial” operation that will happen as long as nothing interferes, plus an equivalent of force laws to describe how objects can influence each other.

He argues that we have no reason to believe in “simple” properties or relations, meaning properties/relations that refer to nothing but their subjects/relata, and so we shouldn’t build our metaphysics out of these.  He proposes gauge theories as a counterexample, in which vectors on fibers at different base points can only be compared via a connection and a connecting path on the base manifold.  As a proof, this would be begging the question, because the spaces that make up the fibers in a fiber bundle usually have an inherent homogeneity to them which “simple” qualities (if any exist) would break.  However, the proposal is valuable for shifting the burden of proof.  Do we have any reason to believe in simple properties and relations?

Maudlin believes that time actually “passes”.  He’s not a presentist, so he’s not running afoul of relativity in this.  I usually say I don’t believe time passes for the same reasons Maudlin doesn’t believe that time “flows”:  what could it flow with respect to?  Doesn’t flow just mean change with respect to time?  But if “passing” isn’t the same as “flowing”, what does it involve?  Maudlin finds it difficult to explain.  It includes an asymmetry between past and future.  This is supposedly not the whole of what it means for time to pass, but Maudlin’s arguments are mostly aimed toward showing that such an asymmetry is plausible (and not reducible to differences in entropy).  I don’t have any objection to such an asymmetry, so it’s not clear how much Maudlin, who asserts that time passes, and I, who assert that it doesn’t, really disagree.

2 Responses

  1. This is something that bothered me for long, but I am one level lower on this: it is not 100% clear if there are laws of nature, what we do know is that there are predictive models of nature. Not being a scientist, I was quite surprised when I learned that something as simple as two objects moving towards each other going to collide at the sum of their two velocities is not actually true in special relativity, you have to use a more complicated velocity-addition formula. This formula seems more like a model than a law to me, because the simple addition formula is a close enough approximation of the combined velocity at speeds far below relativistic. So the model was made more accurate. Laws of nature are not something you make more accurate, they are what they are.

    Anyhow, it still leads to the question if these formulas, scientific models just happen to predict how things are observed to work, or are they somehow indeed embedded in the nature of things, that is, they are really laws of nature? If they just happen to predict how things work, then they are just curve-fitting. And I sort of feel it in my bones that science must be more than just curve-fitting. There is some kind of a real understanding of things in science, something more than curve-fitting. (Okay, quantum physics experiments at the LHC tend to be highly statistical, which makes them kinda curve-fittingy. But I think they are an exception.)

    So the formulas are somehow embedded in the nature of things, in the fabric of the universe. So indeed they are laws of nature. But how can you embed a formula in matter?

    One very satisfactory solution would be the simulated universe theory. If we are living in the Matrix, then when scientists discover such formulas, they are basically reverse-engineering the code. The code really does run such a formula.

    Moldbug pointed out that the difference between simulated universe theory and the religious worldviews is mostly just aesthetic. If we would believe in living in simulaton, we would believe in something omnipotent, omniscient, arguably omnibenevolent, the difference is mostly if we imagine that as the God of the Bible or some tentacled alien sysadmin or AI running a supercomputer. And I say one could even split that difference saying well whatever that is, that is way beyond the capabilities of our imagination so how we imagine it does not even really matter much, we cannot imagine it accurately.

    Ages ago I was talking with a bright young Catholic priest. I asked him to define God. He gave me this: “God is that which relates to the world the same way man relates to his thoughts.” Hm. Do men create thoughts ex nihilo, not out of themselves, too? But anyway if I would define a man as a purely physical being, brain and other organs, which religious people don’t agree with, I could say the human brain is the hardware and thoughts are the software. Which would make God something akin to a supercomputer running a simulated universe. But of course the analogy breaks down at religious people never agreeing with the idea of men being purely physical.

  2. Dividualist,

    if you feel the code is there, but cannot find the formula, only approximate it, means that such code must come from somewhere inaccessible. so, “purely physical” is not an option. true, the “ghost in the machine” is perhaps similar to a supercomputer, but we have (yet) to see such ghost arise from a purely artificial construction in the physical world, or even figure out how genes get to be so selfish… even if we do, robots would be not much else than another race of intelligent beings in the still limited physical world. heck, they may even adopt our God out of a sense of thanksgiving for creating us their creators, lol.

    the priest you talked to may have oversimplified or botched the explanation anyway, in the sense that the material universe came from God, and reflects it to varying degrees, while God intervenes in it in varying degrees too. meanwhile in humans, the soul came at the same time of conception while body and mind started developing, and is nourished as it opens itself up to the Lord’s grace. so it’s not exactly the same.

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