I was thinking about the meaning of the term 'mind', and wanting to make it less fuzzy. The fuzzy definition is
the element of a person that enables them to be aware of the world and their experiences, to think, and to feel; the faculty of consciousness and thought.
My question is, "how might a physicist define 'mind' using concepts of physics, in order to make its meaning totally scientific?"
The "mind" is not a subject of physics. To a physicist it's an emergent property of certain extremely complicated arrangements of particles and fields. You're far better off asking the question of a neurologist, since this is what they study (they don't have definitive answers yet either, but they have made some progress).
A physicist is a person who on the basis of an academic education engages in the science of physics - not in the science of chemistry, biology or other natural sciences. Hence the domain of physics touches the brain and the mind only in a very superficial way.
From a scientific viewpoint it is one of the tasks of neuroscience to provide a definition of the mind:
I consider “mind” to be the mental capability of information processing.
Important steps are receiving signals, comparing signals with the information stored in the memory, interpreting signals and assessing the information, making decisions which are advantageous for the individual, controlling its behaviour.
Of course, each step of the list can and must be further detailed. The above definition relies mainly on the sciences of informatics and neurobiology, not on physics. But understanding the signal transmission along neurons presupposes some specific knowledge from physics.
In case you ask for a definition not from the viewpoint of a physicist, but from the viewpoint of physicalism: "In philosophy, physicalism is the view that 'everything is physical', that there is 'nothing over and above' the physical, or that everything supervenes on the physical." (Wikipedia)
I consider the viewpoint of physicalism to be too restricted to provide an adequate definition of "mind". IMO information is a separate entity. Hence information does not belong to the ontology of physics. And information processing belongs to informatics, it cannot be reduced to physics.
The mind is not physical, it may operate on a physical substrate, however it's semantics are not there. In an analogy, a film is transmitted through waves and displayed in a TV set, using mechanical apparatus, but the meaning of the film is not on the signal, is in the subjective experience of it. To give physicists to define mind, is to ask a technician to describe a film by examining the electric signals.
Mind appears to be an emergent phenomenon of at least one type of computing apparatus we have to hand, the biological brain. I do not believe it has anything to do with the particular wet chemistry of that, and would be happy to accept a mind emerging from a sufficiently large silicon-based computer, or even a Chinese Room. This is only tangentially related to physics, and so out of scope for it.
How to tell whether a mind exists is another matter. I know I have one, "I think therefore I am", and can induce that you have one too. Dolphins and the great apes appear to have minds, amoeba probably not, and there's a very very long slippery slope between the two, I'll give dogs and horses minds. You don't have to get much bigger bodies than amoeba before it's clear that there's some sort of model of the world in there, with goal-seeking, communication, navigation. The Bees' waggle-dance anyone? I'll "know it when I see it" is already way off the pace.
Will we know when silico-sapiens achieves a mind? We'll just have to ask it when it appears. It will already know, from its LLM components being trained on the world's archives, about the Turing test.
The problem you seek is much larger than you may give it credit. "Mind" is one of the hard terms in philosophy to define precisely. Indeed you quote a definition (emphasis mine):
the element of a person that enables them to be aware of the world and their experiences, to think, and to feel; the faculty of consciousness and thought.
This suggests that discussing a definition of "mind" is at least as difficult as discussing what is called The Hard Problem of Consciousness:
The hard problem of consciousness is the problem of explaining why any physical state is conscious rather than nonconscious.
The name for this problem is coined in 1995, but the problem has been a subject of philosophical debate for a much longer time than that. An answer to this debate would be required for your question to have an answer.
Personally, I find it effective to define it implicitly via the Chinese Room:
Searle's thought experiment begins with this hypothetical premise: suppose that artificial intelligence research has succeeded in constructing a computer that behaves as if it understands Chinese. It takes Chinese characters as input and, by following the instructions of a computer program, produces other Chinese characters, which it presents as output. Suppose, says Searle, that this computer performs its task so convincingly that it comfortably passes the Turing test: it convinces a human Chinese speaker that the program is itself a live Chinese speaker. To all of the questions that the person asks, it makes appropriate responses, such that any Chinese speaker would be convinced that they are talking to another Chinese-speaking human being.
The question Searle wants to answer is this: does the machine literally "understand" Chinese? Or is it merely simulating the ability to understand Chinese?[7][d] Searle calls the first position "strong AI" and the latter "weak AI".
Searle then supposes that he is in a closed room and has a book with an English version of the computer program, along with sufficient papers, pencils, erasers, and filing cabinets. Searle could receive Chinese characters through a slot in the door, process them according to the program's instructions, and produce Chinese characters as output, without understanding any of the content of the Chinese writing. If the computer had passed the Turing test this way, it follows, says Searle, that he would do so as well, simply by running the program manually.
Searle asserts that there is no essential difference between the roles of the computer and himself in the experiment. Each simply follows a program, step-by-step, producing behavior that is then interpreted by the user as demonstrating intelligent conversation. However, Searle himself would not be able to understand the conversation. ("I don't speak a word of Chinese",[10] he points out.) Therefore, he argues, it follows that the computer would not be able to understand the conversation either.
Searle argues that, without "understanding" (or "intentionality"), we cannot describe what the machine is doing as "thinking" and, since it does not think, it does not have a "mind" in anything like the normal sense of the word. Therefore, he concludes that the "strong AI" hypothesis is false.
I would argue that "mind" is that which is necessarily missing from the Chinese Room which is present in a native Chinese speaker, and is the gap missing that prevents us from saying the the AI in the Chinese Room "understands" Chinese. And if you come to the conclusion that said AI understands Chinese, then it is entirely reasonable to come to the conclusion that there is no mind.
Missing from that definition, of course, is the scientifically testable hypotheses. To the best of my knowledge, there aren't any, and that is heavily entwined with why this is considered to be "the hard problem."
I think that the richest proposal not yet falsified is the Hofstadter mind. To Hofstadter, a mind is a tangled hierarchy of strange loops. The concept is slowly introduced and built up in Hofstadter 1979 and restated in Hofstadter 2007 with examples. Quoting Chapter 18 of the latter:
Among the beliefs most universally shared by humanity is the idea "One body, one person", or equivalently, "One brain, one soul". I will call this idea the "caged-bird metaphor", the cage being, of course, the cranium, and the bird being the soul. … In contrast to the caged-bird metaphor, the idea I am proposing here is that since a normal adult human brain is a representationally universal "machine", and since humans are social beings, an adult brain is the locus not only of one strange loop constituting the identity of the primary person associated with that brain, but of many strange-loop patterns that are coarse-grained copies of the primary strange loops housed in other brains.
Several consequences are discussed. The concept of telepresence is examined as an example. A point is made against extremist views of consciousness:
The image of the caged bird essentially implied that different people are like separate dots on the same line, dots having a diameter of exactly zero, and thus having no overlap whatsoever. … The opposite thesis would claim that every person is distributed uniformly over the entire real line, and that all individuals are therefore one and the same person! … The viewpoint of this book lies somewhere between these two extremes, picturing individuals not as pointlike infinite-decimal serial numbers but as fairly localized, blurry zones scattered here and there along the line.
The chapter closes by noting that the concept of death is different under his conceptualization of mind:
In the wake of a human being's death, what survives is a set of afterglows, some brighter and some dimmer, in the collective brains of all those who were dearest to them. And when those people in turn pass on, the afterglow becomes extremely faint. And when that outer layer in turn passes into oblivion, then the afterglow is feebler still, and after a while there is nothing left.
On one hand, death would be gradual; on the other hand, ancestor simulations would be impossible.
Hofstadter has a doctorate from the University of Oregon in physics; his thesis is Hofstadter 1976, where he discovered Hofstadter's butterfly pattern.
The generalized type of what that phenomenon over there is doing; or what such-and-such a phenomenon would be doing if the conditions were thus, as measured thus.
Physicists are empiricists interested in predictions, not philosophers interested in essences or mathematicians interested in mathematical objects.
If we want to do mathematical physics with minds, we would model minds with a mathematical object which captures the way that the presence or absence of a mind, or a certain kind of mind, possibly with coefficients, interacts with the system properties we want to predict.
We may or may not be able to represent certain kinds of things reductively, in terms of more fundamental systems. We can't do that for mind. However, even if we can, we almost never do, because it's almost never useful. And in either case, the model is emphatically not the definition.
For example: Representing a star in terms of the Standard Model and general relativity is probably doable, if you used all of the computing power in the world for a thousand years to compute what the star would do in the next picosecond, but I can do almost everything I want to do for representing a star by modeling it with a sphere and a few coefficients like: emissivity, temperature, velocity, mass, etc, depending on what I want to calculate. And in any case: a star is not a zillion ziggabytes of computer code any more than a star is a platonic geometrical solid with some numbers attached. A star is what that stuff over there is doing.
There's not even any reason for a physicist to be a physicalist (if being a physicalist is a thing that it means anything to be, which I doubt, but that's another matter). The only ontological commitment you need to define things the way that a physicist should be defining things is the commitment that there's such a thing as reality and it's the sort of thing we can make mostly-reliable predictions about with scarce information.
The mind is not something physicists can conceptualize. It is primarily biological in nature -- as we know it, it is a feature of some living organisms. Therefore it's a job for biologists. Note that physics cannot conceptualize life itself, even that of the simplest organisms, let alone the mind.
NB: Evidently, the brain is an organ, a living thing. When it's dead, you can try and pump electricity into it like Dr Frankenstein, but it works only in the movies.
Likewise, the body that sustain this brain and benefits from it is a living organism.
The idea that a chair is endowed with a mind is not scientific. A chair wouldn't know what to do with it.
These are platitudes, of course. But they are the reasons why I see the mind-body problem as essentially a problem for biologists, who take the phenomenon of life seriously, and have developed a lot of concepts to precisely try and understand life.
Physic fetishism is fetishism for the small and simple stuff.
"Mind" is a word in an english language, no less, no more. Remember that languages exist to communicate meaning, and meanings of parts of language change depending on context and its users. As such, to get a concrete definition of mind, you need a concrete person in a concrete context.
Though in my experience, people seem to use mind to describe structures that allow an object to react non-trivially to an environment. Sometimes they add self-awareness to the meaning too. Obviously, 'non-triviality' is subjective: some people may find other humans mindless, and some may find the reactions of a bacteria as a primitive kind of mind.
A physicist measures things. Or think about things that can be measured.
If there is a way to measure "mind" then they will measure it and make fancy statistics, and maybe even some predictions.
If you cannot measure it it does not exist for physics.
There are of course things that could be objectively measured but are not interesting for a physicist. Say "boredom" - by measuring brain activity but this is not interesting for a physicist because it is way too high level
I guess, in a physical world, you could try to differentiate "mind" as a subset of the electrical signals generated by the central nervous system specific only to humans. But other people would tell you that some animals possess a higher degree of self-awareness and abstract thinking than some unfortunate human beans. After all, the definition of the mind will be the subject of personal interpretation.
