> although mental states, events and processes have genuine causal powers, the causal relationships that they enter into with physical entities cannot be explained by appeal to fundamental laws of nature

The claim is that mental events are supernatural?

No, the claim is that an explanatory framework limited to physical terms is not complete enough to encompass mental events.

I’m not sure if I’m reading you right. You seem to be saying some mental events don’t have physical causes, or maybe that some mental properties are not encoded physically.

In which case it sounds like there should be some mental events or experiences that are impervious to physical interference. So for example there is no conceivable physical intervention that could affect them. Do you believe there may be mental phenomena that are not causally related to physical processes in that way? It sounds like this should be testable.

"You seem to be saying some mental events don’t have physical causes, or maybe that some mental properties are not encoded physically."

I think he is only saying that an empirical language alone will not be enough to relate mental processes to physical ones. You have to define what a mental event really is before you can properly test anything about it, and depending on what definition you choose it might be inherently un-testable. If you define a mental process as being composed of physical processes from the start then of course you will conclude that all mental processes are influenced by physical ones. There are other possible definitions though such as physical processes being composed of multiple mental processes (the opposite of the last) in which case no physical test could be performed to verify a "change" occurred in the mental subject (but a "mental test" of sorts might still be able to tell us)

The existing terminology may be inadequate. But when we discovered atomic forces, and it turned out that Newtonian physics could not accurately describe them, we did not split the natural world at that boundary and claim atomic forces could not be explained by "appeal to fundamental laws of nature". No, we developed our understanding, phenomena that occurred inside nature came to be considered natural. Our understanding of what the physical world consisted of grew, it did not fragment.

the claim is not that they are not explained by laws of nature, but that they are not explained by physics.

It's like saying you can't model a football game in terms of the behavior of proteins. Sure there are proteins, and there is no magic anywhere, but the conceptual gap is just too vast.

Right, so they are meta-phenomena. They are still entirely physical. The actual process occurring is physical, but there is information being processed and meaning in what’s happening that can be analysed independently of the physical substrate.

It would be better to claim cannot be complete enough, and AFAIK that's still an open question. But people on HN don't seem to think it's a question at all, which shouldn't be the case.

They don't have to be supernatural because they could still host hypotheses that are observable and testable, and don't have to contradict other natural phenomena; but it could be that we would never be able to resolve in-practice how they connect to other phenomena with clarity.

No, the claim is that not everything in the world is physical, even if it all supervenes (is constituted by) the physical. See David Chalmers on property dualism and natural versus logical supervenience. Also, there is panpsychism and other versions of dualism. None of that needs to be supernatural. It's just a question of what the natural world is made up of.

If it's entirely determined by physical stuff thats a contradiction. It may be very complicated, but its still physical.

No, because the reduction in-principle would fail if the system's description language could not support explaining the phenomena in the higher level. And going the other way, it could be impossible in-principle to conduct the experiments that get a complete description because the tools required break how it was originally organized.

It's also not just about adding more variables because "it's complicated". Biology for example seems to be highly reflexive, that sort of behaviour can't really be accounted for in basic causal models. At best we have models which resemble fluid dynamics, and fluid dynamics is only as good as it is because we don't reduce the phenomena down to every molecule.

See also: https://www.scottaaronson.com/blog/?p=3294

And yet nobody claims that fluids are supernatural and above the laws of physics. It's our ability to understand, explain, and model it that is deficient, not the phenomena that is supernatural.

Why mention the supernatural? The question is whether all of nature is reducible to physics, or whether there are strongly emergent/irreducible phenomenon. It's all nature, it's just a question of ontology. It's always logically possible that the world has non-physical properties. Physicalism is an assumption.

To my mind what matters at a physical level is something I’ll call causal significance. Is the property in question a cause of anything physical such as a behaviour? If so, then that property must have a physical basis in reality even if it is simply a physical encoding in cells or chemicals.

A for loop in a computer program is a property. It causes a behaviour. It can only do that because it is encoded in the materials of the computer. The question is, are there any properties a biological system can have that are not encoded in its physical constituents? Anyone answering ‘yes’ to that question really needs to provide a very clear answer as to how they think that might be possible and how else that property might arise.

> The question is, are there any properties a biological system can have that are not encoded in its physical constituents? Anyone answering ‘yes’ to that question really needs to provide a very clear answer as to how they think that might be possible and how else that property might arise.

I believe the answer is that there are properties which only come into existence once you have the right physical arrangement, but these properties can't be predicted in advance from the physical constituents.

As to how it could be possible that truly novel properties come into existence, that's not really different than how it can be possible that QM can have indeterminate properties, or anything that's physically fundament for which we have no explanation. Something happens to exist, and we don't know whether there is answer to why anything exists.

There's also other possibilities, like the existence of abstract and universal entities, such as numbers or universals. How is it that every electron has the exact same charge and mass? Is electron a universal? Why does math work so well for physics? Are there laws of nature that govern the world (make it be a certain way as opposed to just being regularities)? That sort of thing.

>I believe the answer is that there are properties which only come into existence once you have the right physical arrangement, but these properties can't be predicted in advance from the physical constituents.

In order for such properties to not be predictable from the physical constituents, they must not be encoded in the physical constituents. If they are encoded in the physical constituents, then they must be predictable from them.

If these properties are not encoded in their physical constituents, where does the information come from and where is it represented?

Supervenience is the relation of being made of a substrate, but not predicted by its laws. Supervenience is distinct from entailment, you are conflating the two. https://en.wikipedia.org/wiki/Supervenience

Suggesting that the natural laws are such that all behavior must be entailed by "lower level" natural laws, is a stronger position than stating that all things follow natural law. I think it is hubristic to think that somehow our understanding of natural law is exempt from the same issues that are raised by the incompleteness theorem in math.

Can you always recover all physical information?

I would be interested in seeing if two neural network models with equivalent topology and weights could always be said to 'have' the same subject matter. (It's a better example than for-loops, because I think both brains and computers can embody what it means to have a neuron in a close-enough fashion).

I would expect the answer would be "no". You would have to know about the environment that trained them, which blows the door open for something which is irreducible without knowing about environmental conditions, and biology having too rich of an environment to be as precisely reducible as computers might ever be without them being also a computer system.

In my other posts in this thread I emphasize the "in-principle" and "in-practice" distinction because I don't believe it is the "in-principle" part of reductionism that ought to be at stake. It's if we can actually do it in a way that doesn't invite approximations.

To see why you can't confuse reductionism in-principle with reductionism in-practice, you could read this paper:

"More is Different: Broken symmetry and the hierarchical nature of science" http://robotics.cs.tamu.edu/dshell/cs689/papers/anderson72mo...

Science divides into different disciplines precisely because the units and laws of one model do not close over the phenomena of another.

Science divides into disciplines because human compute power and lifespans are limited.

Anderson is right to point out that reduction is easier than construction. I deny him the implication that construction is fundamentally impossible, only that it is out of reach of current human knowledge.

Nothing prevents a Demon from starting with first principles of natural laws and matter, sitting and pondering for infinity, and writing a treatise on any number of emergent phenomena, say: realpolitik between countries made up of parties made up of people made up of organic matter made up of atoms made up of...

We know this must be possible because it must have happened at least once, in the mind of the demon we call reality.

I get the distinction you're making between in-principle and in-practice, but this is an accident of our capabilities. Any gaps between the sciences is due to our ignorance. Sadly it seems human scientists desire to claim their corner of science is strong, independent and just as "fundamental" as any other's, and like playing up these gaps in our knowledge. I don't understand this desire to draw permanent boundaries based on arbitrary human limitations, and so quickly declare non-overlapping magesteria.

Nothing of what I said implied that the boundaries should always be expected to remain permanent for any typical pair of disciplines (although there will be disciplines where that holds). There are instances where boundaries have been productively crossed and fields merged. And it's certainly more productive to try to get simpler explanations using past hypotheses between disparate phenomena – as long as no information is lost. But that doesn't remove the limitations, and the only desire here is to understand and know these limitations. That's as scientific an endeavour as any.

If it's a matter of the framing that makes you sombre, consider the alternative where being a finite observer with the capacity for self-reflection such as ourselves is put in a situation where we can navigate alternative descriptions of reality, never having to terminate with a final explanation, yet always growing in personal understanding... this is what your Demon would actually be doing, for if it were as powerful as you imply, it would not be a scientist at all. It would simply be reality, with these observers the lesser of it.

Maxwell's Demon might have a thing or two to say to you. The fallacy is to believe that reduction is a total property of the territory, rather than a property of some of the territory that lends to a certain kind of map. We know that there are phenomena in the world with strong boundaries and there are phenomena with weaker boundaries. It may be that at low scales things can be easily separated, but that doesn't have to translate to how easy it is to tease-apart macro-phenomena.

Heck below atoms, which lend themselves most strongly to the reductionist intuition, we have quantum waves. The wave-particle duality should at least simultaneously give reduction and non-reduction some credence.

I won't argue that some phenomena may be resistant to reduction beyond human capability to reduce. My main problem with the thesis is that whatever irreducible phenomena that is, is still part of the natural, physical world. Because we lack the knowledge to fully map thoughts to underlying atomic events does not mean thoughts are suddenly supernatural and non-physical. They are a different category of physical event, perhaps.

Maxwell's Demon is new to me, and I'm not quite sure how to interpret it in this context. At first read, the claim that the observing, calculating, acting Demon, manipulating a physical trapdoor is not part of the thermodynamic system seems... laughable.

> I won't argue that some phenomena may be resistant to reduction beyond human capability to reduce. My main problem with the thesis is that whatever irreducible phenomena that is, is still part of the natural, physical world.

You don't have to posit the supernatural. People conflate believing in a single objective reality with having to believe in strong materialism (or worse, atomic materialism, when QM goes deeper), when all you have to do is believe that reality is consistent. You might not be able to create a total consistent model of reality, but if reality is consistent then you don't have to propose extra-physical forces due to conservation of energy or other such constraints. You can exclude contradictory hypotheses even if you can't settle on the "actual" one, even in-principle.

In which case you can have models in one domain of science, and models in another domain, which may not connect with each other, but they don't have to contradict each other either, and you can do this all while not believing in the supernatural or denying an objective reality.

> Maxwell's Demon is new to me, and I'm not quite sure how to interpret it in this context. At first read, the claim that the observing, calculating, acting Demon, manipulating a physical trapdoor is not part of the thermodynamic system seems... laughable.

That's the immediate refutation a lot of people propose, but then to model that demon plus the system is to also become another demon. So you can't escape this problem as long as you are not an abstract ideal observer, which none of us are in practice.

(The fact that it's laughable is correct, because it could never happen, including to us.)

By analogy, computers don't write software programs. Programs 'run' in a physical environment, but I'll assert that higher levels of their 'behavior' when they interact with the outside world (for non-trivial programs) are non-transparent to someone who can only observe the physical computing elements.

The individual mind is far more complex than any existing programs. We are certainly not aware of all of the aspects of the world it is responding to. Furthermore, the diversity of those responses across the population is staggering. 'Irreducible' seems like the right adjective at present.