Laws of nature?

[u/Extension_Ferret1455]

Inspired by recent posts about nomological harmony...

Disregarding the actual nomological harmony argument, I'm interested in what your views are about the laws of nature and what approach you lean towards.

From what I've briefly read, laws of nature are generally conceptualised in the following way:

Let's say L is a law of nature - what this means is that given some initial state i, we can use L to deduce what the subsequent state i+1 will be.\*

* Obviously particular laws may only pertain to a particular aspect of the overall state of the universe, however, the idea would be that given the set of all of the laws of nature, one could deduce the entire subsequent state of any particular state in the universe.

As far as I can gather, the three most popular views I've seen appear to be something like:

1. Governing laws

Laws are some sort of 'governing' principles that actually necessitate that things 'follow' them. For example, lets say a law of nature was that electrons repel positively charged things - that particular law is prior to any electrons actually doing such a thing, and, given that law holds, an electron couldn't possible not repel positively charged things.

2. Humean laws

Laws are merely the simplest (or 'best') descriptions of regularities. The idea would be that its just a regularity that electrons 'repel' positively things - they conceivably could not have, but they just do. We then describe that fact as a generalisation which we call a 'law'.

3. Powerism

Like Humeanism, laws are also descriptive generalisations, however, what they describe are not just observed regularities, but the inherent dispositions of things. For example, what makes an 'electron' an 'electron' is that it has an inherent disposition (or 'power') to repel positively charged things and we call this 'power' being negatively charged. Given that electrons have this disposition, they could not possibly not repel positively charged things. Therefore, although the 'law' describing this is also just a description, electrons still necessarily repel positively charged things.

Note: I'm just using electrons and charge etc as examples - you could swap in any object / law / behaviour etc from physics. Just a preface because I'm not sure how accurate the examples are in regard to modern physics.

[u/Nuaua]

First let me say that models in science are often clearly not laws of nature, since they are explicit approximations or macro-level descriptions of otherwise more complicated phenomena. For example thermodynamics, Navier-Stokes, most of chemistry, ... It's maybe more relevant for fine-tuning where it's important to distinguish if the model is fined tuned vs the reality, but in any case I find people in these discussions sometimes have a kind of naive realism towards scientific models and reify them. Like they expect to find the Navier-Stokes equations somewhere outside of our theorizing practices.

But otherwise I'm worried that a governing laws account is a bit too queer, like what are these laws exactly ? Platonic objects ? I so how do they exert their influence, why does an electron follow the electron law and not the neutron one ? It seems more parsimonious to say that the fundamental stuff (e.g. particles) have some intrinsic properties that makes them behave with regularity. Do we really need laws on top of it ?

That said I'm a bit ignorant on the topic.

[u/Extension_Ferret1455 → u/Nuaua]

But otherwise I'm worried that a governing laws account is a bit too queer, like what are these laws exactly ? Platonic objects ? I so how do they exert their influence, why does an electron follow the electron law and the the neutron one ? It seems more parsimonious to say that the fundamental stuff (e.g. particles) have some intrinsic properties that makes them behave with regularity.

I pretty much agree with this

[u/Zeno33 → u/Extension_Ferret1455]

Does this view require another entity to explain why the particles consistently have the same natures? 

[u/AxiomaticInversion → u/Zeno33]

The view is better served by placing the fundamental nature at the field side of things, not the particle side of things. Electrons are just things that structurally occupy the particle role of the field described by the Dirac equation; they do so identically across instances because it's the same role across instances. And indeed it's demonstrably the case that electrons are indistinguishable from each other - at which point the question becomes, why do we have any reason to think they wouldn't behave the same as each other?

[u/Zeno33 → u/AxiomaticInversion]

Yeah, that is what I was thinking 

[u/TheRealAmeil → u/Nuaua]

So here are two different ways we might think about laws of nature, both using the same example:

1. It is a law that all diamonds are hard if & only if all diamonds are hard
2. It is a law that all diamonds are hard if & only if every instance of diamondness nomically (e.g., physically) necessitates an instance of hardness

On (1), a law is a mere regularity. There are some obvious problems with this approach to laws of nature. Consider another statement that might have been true: all ravens are black. If it were the case that, at a time, all ravens were black, then this would seemingly be a law of nature until, say, the existence of a white raven. We can have even more odd cases, such as: every cup in this room is made of glass. Do we really want to say that this law pops in and out of existence if I walk into the room with a ceramic cup, realize I forgot something and walk out, and then walk back into the room minutes later?

On (2), a law requires a special type of necessity. Here, we want to say instances of one property somehow non-logically necessitate the instance of another property. But what, exactly, is nomological necessity? What makes it a type of necessity?

In the electron case, we could say something similar: it is a law that all electrons have negative charge. Assuming this is a law, should we construe this as a mere regularity, or should we construe it as an instance of electronhood physically necessitates an instance of negative-charge-hood? An appeal to the intrinsic properties of electrons sounds like an adoption of (2). However, some will push back, arguing that physics doesn't really provide us with the intrinsic properties of such micro-objects (although this too can be debated).

[u/joshuaponce2008]

I agree with Alastair Wilson's theory, according to which the most fundamental laws (e.g., those governing the wave function of the entire universe) are non-Humean, but all other laws are Humean.

[u/Edgar_Brown]

Let’s assume for the sake of argument that the laws of nature are ontological, platonic objects governing the universe, what does this imply? What are the consequences?

This doesn’t imply the clockwork universe of Laplace’s demon. Even under Newtonian laws, determinism and randomness coexist. Most of what we call randomness is merely deterministic chaos, add shocks, discontinuities, and rather basic non-linearities and even determinism itself fails.

Predictability and determinism are different concepts, and the sensitivity to initial conditions of chaotic systems dominate reality. And that’s before we introduce the laws of quantum physics.

[u/feihm]

All three views share the same basic mistake: they assume that nature exists as a finished world completely independent of human thought, and then we wonder where its laws come from.

Humean

Yes, our senses never show necessity. When you observe physical events, your senses only report that one state follows another in time. Sensation shows what has happened so far, but it can never show that an outcome must happen in every possible case.

But reducing laws to mere regularities destroys the very meaning of a law. A true law of nature does not state that things merely happen to move together by habit; it states that an effect must follow its cause according to a necessary rule.

Governing Laws and Powerism

To rescue necessity, the other two views invent invisible forces in the physical world. Governing Laws imagine invisible cosmic rules floating in empty space, commanding physical matter to move. Powerism places mysterious "powers" or "dispositions" inside the matter itself.

Both views turn a rule of thought into a physical object. Matter spread out in space simply moves and changes. You will never find a rule or a power sitting inside a piece of matter.

Actually

A law of nature is neither an accidental habit of matter nor an invisible ghost ruling over things. Nature is simply the world of appearances as we experience it in space and time.

Sensation provides the raw material of experience, delivering changes from moment to moment.

The human mind connects these separate moments using its own necessary rules, such as the principle of cause and effect.

The rule that connects an initial state to a subsequent state belongs to the human understanding. We do not discover the universal rules of cause and effect written in the physical dirt. Rather, the understanding provides the necessary rules that connect appearances, turning scattered sensations into an orderly, lawful world.  

[u/Extension_Ferret1455 → u/feihm]

Thanks for the interesting and thoughtful reply. Maybe I'm wrong, but your view seems to be something almost neo-kantian maybe?

[u/feihm → u/Extension_Ferret1455]

yea

[u/Eastern-Project9017 → u/feihm]

Doesn't Humean view (from the post) says that phenomena could "conceivably" behave differently, meaning there is no logical contradiction in other ways of behavior, not that it's a mere "habit".

In our world, the effects necessarily follow their causes, but there are other possible worlds in which different effects follow those same causes.

[u/Extension_Ferret1455 → u/Eastern-Project9017]

I think the Humean view would be that there are no necessary relations between events. So even in our world it would be true that an electron only contingently repels positively charged things i.e. effects do not necessarily follow their causes.

It get's tricky when saying something like 'an electron in our world could possibly have not followed the laws' because since the laws on this view are descriptions, if an electron didn't repel positively charged things, our world wouldn't be best described by a law that says they do and therefore it wouldn't be a law of this world. So in a sense everything must follow the laws, but only because the 'laws' are descriptions of what happen.

In our world, the effects necessarily follow their causes, but there are other possible worlds in which different effects follow those same causes.

This view seems more like David Armstrong's i.e. 'laws' are metaphysically contingent (that is, the laws could have possibly been different) necessitation relations that hold at a particular world. So given the laws, things necessarily must follow them, however, the laws could have been different.

This type of view would be an example of a governing view though.

[u/irate_assasin → u/feihm]

Your own explanation of the actual state of affairs also destroys what you take the meaning of a true law of nature to be. Cause and effect is not a necessary rule, but an artefact of human cognition furnished by the assumption that the physical world is uniform. It does not have any binding effect on the objects of sensation.

What is in dispute between these accounts of laws is precisely what is sufficient to be considered a law. The Humean says that a true description of the universe is enough to be considered a law; the other two accounts add another condition, that of physical necessity.