What are Laws of Nature?

I recently came across this presentation that Ed Feser gave at Fermilab:

https://vms.fnal.gov/asset/detail?recid=1955775&recid=1955775

I think here (and in some of his other writings) he makes a pretty good case that the laws of nature are really the laws of natures: that the way the physical world operates is grounded in the intrinsic properties (specifically, the causal powers and liabilities) of physical things.

Looks like that 2500 year old Aristotle guy may have gotten some things right after all. :wink: Thoughts?

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I won’t be listening all the way through. And I already disagree with Feser’s Aristotelean view. My own view is closer to what he called the Instrumental view.

its only Gods laws. Or rather a system set up on creation week and finished on the sixth day. there has been no new creation or laws since.
its just a settled conclusions to the universe in how it operates. It does not have a mind of its own but is only a computer program. then the fall came and ruined things. Yet all physics and biology still operates within a corrupted system or laws.

@structureoftruth, do you think there are “laws” of nature?

Mind if I ask why that is? What problems do you see with his view?

Are you an anti-realist about science, then? I find it hard to see how one can be seen instrumentalist about laws of nature without being one about science more generally.

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What do you think of Feser’s critique of this conception of the laws of nature?

I’m inclining towards the view Feser presents here, which is that things have natures or essences, and the laws of nature describe how things tend to operate given their natures (and specifically, the casual powers inherent in those natures).

Those natures and causal powers may be reducible - maybe the fundamental entities are quantum fields, for example, and the laws of physics describe the way they interact with each other given their intrinsic properties.

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Hi everyone,

Undoubtedly, many laws of nature can be sensibly construed as laws of natures, as Professor Feser argues. But what about conservation laws? Have a look at this article on Noether’s first theorem. As far as I can make out, the theorem applies not to this or that entity, or even to the cosmos as a whole, but to physical systems in general:

As an illustration, if a physical system behaves the same regardless of how it is oriented in space, its Lagrangian is symmetric under continuous rotations: from this symmetry, Noether’s theorem dictates that the angular momentum of the system be conserved, as a consequence of its laws of motion. The physical system itself need not be symmetric; a jagged asteroid tumbling in space conserves angular momentum despite its asymmetry. It is the laws of its motion that are symmetric.

As another example, if a physical process exhibits the same outcomes regardless of place or time, then its Lagrangian is symmetric under continuous translations in space and time respectively: by Noether’s theorem, these symmetries account for the conservation laws of linear momentum and energy within this system, respectively.

As a final example, if the behavior of a physical system does not change upon spatial or temporal reflection, then its Lagrangian has reflection symmetry and time reversal symmetry respectively: Noether’s theorem says that these symmetries result in the conservation laws of parity and entropy respectively.

Physical systems don’t all share a “common nature,” unless one postulates a “form of corporeity” common to all material objects, underlying the specific forms they possess as objects of this or that kind. I believe Albert the Great thought along these lines, although his disciple, St. Thomas Aquinas, disagreed with him and insisted that each thing had one, and only one, substantial form which makes it the kind of thing it is.

Alternatively, on could suppose that the various symmetries which characterize physical systems in our cosmos reflect rules which are imposed on the cosmos and everything in it, by a Cosmic Rulemaker.

Thoughts?

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I’m not quite sure what it means to be anti-realist about science. It seems reasonably obvious that science itself is a human construct. But there is a reality independent of us, and science attempts to describe that reality.

I don’t think that Noether’s therem presents special difficulty to the Aristotelian. It is more of a mathematical theorem which is necessarily true given certain conditions. Why some physical objects behave in that way (i.e. having a symmetry in its Lagrangian, which by Noether’s theorem implies a conservation law) is the question. It could be in the “nature” of the system to have such symmetries.

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@structureoftruth this seems to be a radical reductionism. I’m not sure…

I think your view is probably how to make most sense of Aristotelianism and modern physics. Still, what’s interesting to me is that most Aristotelian-Thomists tend seem to hold the view that these lower-level entities don’t actually exist in the real world, because they always combine with each other to form new substances which have their own causal powers. (I’m getting this from reading Feser’s Aristotle’s Revenge - still in progress - and talking with some Thomists.) The classic example is water - a Thomist would typically say that hydrogen and oxygen don’t really exist in a molecule of H2O - they only virtually exist. Same goes with protons, neutrons, and electrons, which only virtually exist in the oxygen atom (which is itself, also only existing virtually in the water molecule). This virtual existence goes all the way down to quantum fields.

In fact, some Thomists may argue that even H2O also only exists virtually in the bodies of water that we encounter everyday. Bodies of water, however, are sort of privileged in that we can see them change directly in everyday life and are thus exist in a “real” sense.

Thus, in an A-T perspective, as Feser mentions near the end of his talk, the explanatory hierarchy is inverted: fundamental laws and entities don’t have more explanatory power than the macro-level things like tables and chairs and puddles of water. Instead, the fundamental laws are only true because of the inherent causal powers in the substances that actually exist.

@Eddie, @jongarvey or others can correct me on my representation of Thomistic views if I’m wrong. For me, this is the most baffling and anachronistic part of the Aristotelian philosophy of nature, though I could be interpreting Feser or A-T philosophy wrongly.

Yes, I’m still trying to wrap my head around the broader metaphysical system that Feser adheres to. As far as I do understand it, you have it correct - and it seems very strange since (for example) the reduction of the behavior of a chemical substance to the behavior of its constituent electrons and atomic nuclei seems so powerful, in explanatory terms. You’ll have to let me know how Aristotle’s Revenge is! I want to read it but haven’t gotten a hold of it yet.

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I’m not sure either! :slight_smile:

I think individual natures could explain conservation laws without too much difficulty: it is part of each individual nature that it cannot gain or lose momentum, for example, without transferring from or to something else. The question then would be why each individual nature has those properties. (Which is really just another way of asking why these natures exist instead of others, which probably comes down to God’s creative decision.)

I think you’re representing Feser broadly correctly (though I’ve not read Aristotle’s Revenge the same idea on water occurs elsewhere.)

Anachronistic? I’m not sure: reduction of entities to their parts is one approach, but I’m not sure why it should be intriniscally preferable to the idea that water has its own “essence” beyond its constituents. The question might be insoluble, or it might be resolvable by looking at the detail of whether water’s properties can, in fact, be explained by the properties of hydorgen and oxygen or not.

But that’s a question of scientific investigation, rather than anything to do with “anachronism.” What’s baffling with the telescope one way round might, just possibly, be explicable with it reversed.

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The anachronism that I see is not to do with the general idea of things having causal essences or powers, but the fact that Thomists tend to apply them to substances without a clear consensus on which entities correspond to substances in modern physics.

As @structureoftruth has suggested, quantum fields (or something similarly fundamental) seem to be the most obvious choice to assign causal powers and “real existence” to. However, most Thomist philosophers still tend to talk about everyday phenomena like the causal powers of water. They “privilege” the everyday level of existence that we can access directly with our senses (and the main one which Aristotle had access to, thousands of years ago) instead of the things that physicists observe today - quantum fields, electrons, protons, neutrons. When pressed on the point, Thomists like to punt the question away, saying that what constitutes a “substance” is something for scientists to investigate, not philosophers. But most scientists today are not Thomists, so we don’t understand how to apply this potentially useful philosophy of nature.

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What I’ve found interesting is that Werner Heisenberg privileged the “macro” world of experience in exactly the same way, and even used Aristotelian arguments to do so. For that reason, you might find his Physics and Philosophy an interesting (and short) read.

A related set of eideas from someone who understood quantum physics from its inception is Arthur Eddington’s The Nature of the Physical World.

Both these books have the value of challenging ones assumptions about what is “primary reality”, and both come from leading physicists rather than armchair philosophers.

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This might be unfair of me since I haven’t read Heisenberg directly (though I have now gotten a hold of Physics and Philosophy and will take a look!), but I feel at least part of the reason Heisenberg takes this position is to support the Copenhagen philosophy of quantum mechanics which had already taken shape. But it seems to me that there are far better ways of interpreting QM than Copenhagen, such as Bohmian mechanics.
Of course, even Bohmian mechanics has aspects which are difficult to countenance from a reductionistic perspective - the wavefunction(al) is a holistic property of all the particles (or fields) throughout the universe. So there is maybe still a sense in which individual particles (or field regions) don’t exist except as part of a larger system. Hmm…

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Hi @dga471,

Still, what’s interesting to me is that most Aristotelian-Thomists tend seem to hold the view that these lower-level entities don’t actually exist in the real world, because they always combine with each other to form new substances which have their own causal powers…The classic example is water - a Thomist would typically say that hydrogen and oxygen don’t really exist in a molecule of H2O - they only virtually exist. Same goes with protons, neutrons, and electrons, which only virtually exist in the oxygen atom (which is itself, also only existing virtually in the water molecule). This virtual existence goes all the way down to quantum fields.

I have to say I have a problem here. Either a thing exists or it doesn’t. Virtual existence is a cop-out. According to Thomists, I have one and only one substantial form, and when I die, my corpse has another form entirely. The only thing in common between me and my corpse is prime matter, which is pure passive potency, devoid of any positive characteristics at all. So by rights, there ought to be nothing in common between me and my corpse - and yet they both have the same shape, size and mass (at least, immediately after my death, they do). Thomism doesn’t provide a good explanation of this fact.

Likewise, the suggestion that water is not composed of hydrogen and oxygen is frankly absurd. If it’s not composed of hydrogen and oxygen, then what the heck is it composed of? What are you going to call the two smaller atoms in a water molecule, if you’re not going to call them hydrogen atoms? Thomist arguments purporting to prove that water isn’t composed of hydrogen and oxygen are weak. I’m looking at Ed Feser’s Scholastic Metaphysics, page 178. Feser quotes an argument by Professor David Oderberg, that if water contained actual hydrogen, we should be able to burn it - but in fact, the opposite is the case. However, this argument only shows that water is not composed of hydrogen and oxygen molecules - but then, who said it was? Water is composed of hydrogen and oxygen atoms, which retain the micro-level properties of hydrogen, even if they lack the macro-level ones which we commonly associate with this substance. At standard temperature and pressure, hydrogen is a nontoxic, nonmetallic, odorless, tasteless, colorless, and highly combustible diatomic gas with the molecular formula H2. Whether hydrogen atoms will react with oxygen depends on what (if anything) they’re bonded to. While free-floating hydrogen radicals are highly reactive, hydrogen atoms which are already bonded to oxygen in a water molecule are obviously less so. But that doesn’t make them something other than hydrogen.

I don’t think that Noether’s therem presents special difficulty to the Aristotelian. It is more of a mathematical theorem which is necessarily true given certain conditions. Why some physical objects behave in that way (i.e. having a symmetry in its Lagrangian, which by Noether’s theorem implies a conservation law) is the question. It could be in the “nature” of the system to have such symmetries.

But in A-T metaphysics, “system” is not the name of any kind of natural entity, such as a horse or a palm tree. There is no substantial form of a system, as such. Hence it lacks a nature. Do you see now why I am perplexed?

Finally, on page 183 of Scholastic Metaphysics, Feser expresses skepticism regarding the notion that there could be fundamental particles that are incapable of substantial change. But it strikes me that quantum fields could be said to perdure through time: they’re always there, even if particles are continually popping into and out of existence. Thoughts?

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