How physicists handle the idea of Free Will?

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  • #126
sophiecentaur
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In any case, I agree that how you define responsibility, free will and responsibility are a package deal.
Yes; it's definitely a package..
I see it this way: responsibility is the influence of the group on the individual. It is a normalising influence which may not immediately appeal to the individual. We have 'free will' in as far as we are not totally aware of all the influences on us (looking from inside the game) and, when we come to a decision, it is based (to a varying extent) on what we perceive as our 'responsibility' which is, in fact, an urge to a particular preferred action, which we learned from society.
 
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Hi pftest,

Logical supervenience is a concept like the terms "intrinsic" versus "extrinsic", and like those terms, it attempts to pick out a relationship between properties. In this case, logical supervenience tries to pick out properties that relate. So the argument is, "Do mental states logically supervene on physical states?"

For the record, logical supervenience is nicely defined here:

Let's then ask the question as Chalmers did, do mental states logically supervene on physical states? Could we for example, imagine a Turing machine that could consistently pass a Turing test that does not support mental states? That is, is it possible that such a machine could only have physical states? Note that mental and physical states here are defined as Jaegwon Kim defines them.

Clearly, a Turing machine produces responces based on algorithmic manipulations of symbols. Those algorithms can be described mathematically and are deterministic. So for each physical state through which a Turing machine passes, there is a physical reason for why it passes through that state. There is no need to appeal to mental states in this case in order to explain why that Turing machine produced the set of responces it did in order to pass the Turing test. Such a machine therefore does not need to have mental states in order to produce the behavior, it only requires the physical states. If we accept this, we can say those mental states to not logically supervene on the physical states since we clearly have no reason to suggest that subjective experiences (which can't be objectively measured) should supervene on those physical states, though we still might claim that those mental states naturally supervene on the physical states.

In fact, we can't know if there are ANY mental states that supervene on physical states if the mental states have no influence over the physical states. That problem is known as the Knowledge Paradox as described for example by Rosenburg and Shoemaker.
I think we have talked about supervenience before, but i dont remember the outcome. My impression of supervenience is that a supervenience relationship is always conceptual. So when someone says that your mind supervenes on your brain, it actually translates to "some other mind conceptualises that your mind supervenes on your brain". So a supervenience relationship doesnt describe any kind of physical activity and this means that supervenience isnt a physicalist view of the mind body problem.
 
  • #128
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The external world is a mental construct, the self is a mental construct, I can't think of anything at all that isn't a mental construct.
Idealists think that is true yes, but physicalists think that physical things exist independently of minds.
 
  • #129
sophiecentaur
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Idealists think that is true yes, but physicalists think that physical things exist independently of minds.
So idealists say that the constructs of the mind are, somehow 'greater' than the physical processes that are, in fact, going on in the brain? That implies that they believe a part of us is outside the physical Universe. Apart from the fact that it could make one feel good to think that way, there is no evidence for this, is there?
 
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So idealists say that the constructs of the mind are, somehow 'greater' than the physical processes that are, in fact, going on in the brain? That implies that they believe a part of us is outside the physical Universe. Apart from the fact that it could make one feel good to think that way, there is no evidence for this, is there?
Idealism is the idea that everything is mental. Like physicalism (which holds that everything is physical), it is a metaphysical position and no evidence exists to tell us that either of those positions is right or wrong.
 
  • #131
sophiecentaur
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Yeah, well, when I drop a hammer on my foot, the result isn't just 'mental'.
 
  • #132
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Yeah, well, when I drop a hammer on my foot, the result isn't just 'mental'.
How do you know about your foot, or the hammer? How do we know about anything physical? The entire bunch of sciences, including physics, depends on empiricism, which means "to experience", aka consciousness. So mind really is the starting point of all our knowledge. From the consistency of your observations you may start believing that a physical world actually exists out there, but this is an assumption, not a fact. Of course the idealist view is also an assumption.
 
  • #133
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How physicists handle the idea of Free Will?


Is this somehow supposed to be different or more significant than the questions:

How metallurgists handle the idea of Free Will?
How masseurs handle the idea of Free Will?
How miners handle the idea of Free Will?


If so, why should physicists be more concerned than the above? Why is free will more related to physics than to agriculture or irrigation?
 
  • #134
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Yeah, well, when I drop a hammer on my foot, the result isn't just 'mental'.


If i can hear your scream, i'd agree with you. Otherwise, it'd be subjective/non-existent as far as i am concerned.
 
  • #135
sophiecentaur
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Yes, I was being very trivial there.
Problem with that view is that you and everyone else would need to be just figments of my imagination. That would have to imply that I know more than you and all the others (who are all my dream buddies). It would mean that I taught myself Maths and Physics from scratch..... ?
Perhaps, if I were a 'philosopher' my ego could cope with that.
 
  • #136
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Yes, I was being very trivial there.
Problem with that view is that you and everyone else would need to be just figments of my imagination. That would have to imply that I know more than you and all the others (who are all my dream buddies). It would mean that I taught myself Maths and Physics from scratch..... ?
Perhaps, if I were a 'philosopher' my ego could cope with that.
That would be solipsism (only your mind exists). Solipsism is a form of idealism, but idealism doesnt have to be solipsism, it doesnt specifify how many minds or who they are.
 
  • #137
How physicists handle the idea of Free Will?


Is this somehow supposed to be different or more significant than the questions:

How metallurgists handle the idea of Free Will?
How masseurs handle the idea of Free Will?
How miners handle the idea of Free Will?


If so, why should physicists be more concerned than the above? Why is free will more related to physics than to agriculture or irrigation?
You left out brick layers. We brick layers have a very comprehensive theory purporting to explain the universe, if anybody's interested.
 
  • #138
sophiecentaur
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That would be solipsism (only your mind exists). Solipsism is a form of idealism, but idealism doesnt have to be solipsism, it doesnt specifify how many minds or who they are.
That implies 'souls' that can communicate with each other. Difficult.
If I had to, I'd rather be a solipsist. But all that stuff fits in so well with the explanation of it all being generated by our minds and that is a relatively simple idea.
 
  • #139
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Idealists think that is true yes, but physicalists think that physical things exist independently of minds.
I think I would have to define myself as an idealist in the Kantian sense. We can only know the external world through our senses, and therefore the external world is an unobservable hypothesis. This doesn't mean that the physical world doesn't exist independently of our minds though. It just means that we can never know the external world directly (and that we can't be sure it exists).

The fact that we deal with an internal representation of the external world rather than the world itself is widely accepted in Neuroscience. For example: http://philosophyandpsychology.com/?p=1013 [Broken].

"Here we can see the intellectual foundations for modern neuroscience’s claim that the objects we experience are illusionary constructions generated from the brain making hypotheses and guesses about how the world is based on ambiguous sensory input. The key idea here is construction. An internal mental construction implies a disconnection from the objects themselves. When grasping a coffee mug, my vision is not directed towards the cup itself, but rather, towards an internal construction the brain generates. According to Kantian neuroscience, the mug I experience is not real; it is a simulation. Neuroscience is thus an intellectual descendant of Kantian anti-realism. Indeed, 20th century positivism collapsed into representational phenomenalism despite its claim to be “anti-metaphysical” and modern neuroscience has subsequently followed suit with little critical discussion."
 
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  • #140
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So idealists say that the constructs of the mind are, somehow 'greater' than the physical processes that are, in fact, going on in the brain? That implies that they believe a part of us is outside the physical Universe. Apart from the fact that it could make one feel good to think that way, there is no evidence for this, is there?'.
It's more that materialists believe in an unobservable external world which exists outside of anything we can ever directly experience. This is what there is no evidence for. There is plenty of evidence for the existence of mental processes and conscious experience, in fact this comprises everything we ever know as individuals. What you describe in this quote is dualism, which accepts the existence of separate physical and mental entities.

Yeah, well, when I drop a hammer on my foot, the result isn't just 'mental'.
Why not?
 
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  • #141
Q_Goest
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Hi pftest,
I think we have talked about supervenience before, but I dont remember the outcome. My impression of supervenience is that a supervenience relationship is always conceptual. So when someone says that your mind supervenes on your brain, it actually translates to "some other mind conceptualises that your mind supervenes on your brain". So a supervenience relationship doesnt describe any kind of physical activity and this means that supervenience isnt a physicalist view of the mind body problem.
You jogged my memory... I remember talking about this now. I think what you're saying is that the supervenience relationship is conceptual in the sense that it depends on the individual who conceives of the relationship. Different individuals will have a different conceptual relationship so the supervenience relationship isn't consistent between individuals. Is that right?

Supervenience can be broken down into logical versus natural supervenience, but supervenience alone means the following:
Supervenience is a concept with broad applicability throughout philosophy that has particular importance to physicalism. …

Supervenience can be seen as the relationship between a higher level and lower level of existence where the higher level is dependent on the lower level. One level supervenes on another when there can only be a change at the higher level if there is also a change at the lower level. (e.g., a set of properties A supervenes upon a set of properties B when there cannot be an A difference without a B difference). …

Supervenience establishes such a relationship between the mental and the physical, that any change in the mental is caused by a change in the physical. Just as a shadow is dependent upon the position of the object causing it, is the mental dependent upon the physical. Physicalism thus implies (through modal realism) that:
No two worlds could be identical in every physical respect yet differ in some other respect.​
The corresponding conclusion about the mental would be as follows:
No two beings, or things could be identical in every physical respect yet differ in some mental respect.​
Ref: http://en.wikipedia.org/wiki/Physicalism#Supervenience

For example, the pressure of a gas in a container supervenes on the temperature, number of molecules that make up the gas, and the volume of the container. The ideal gas law is used for illustration only; PV=nRT. So we can say the pressure supervenes on the physical state of the gas molecules. Without a change to the physical state of the gas molecules, we can’t get a change in the pressure. If we change one of the gas's properties, such as temperature, the pressure will also change. In this case, the pressure of the gas "naturally supervenes" on the physical state of the gas molecules. This relationship is given by the ideal gas law, PV=nRT. We might however, conceive of a world where the constant R is different and therefore, a mole of gas at a given temperature and in a given volume would have a pressure DIFFERENT than the pressure we know to exist. So the particular pressure of the gas we measure in our world “naturally supervenes” on the physical state according to our equation but it does not “logically supervene” since the value for R could conceivably be different in a different world.
(See Chalmers, “The Conscious Mind” pg 36)

For philosophy of mind, a physicalist would contend that the mind supervenes on the brain in some way. For the sake of illustration, we might consider a physicalist who would argue that the mind is a higher level phenomena created by the interaction of neurons in the brain. Therefore, the mind supervenes on both these interactions and on the neurons themselves. This is a supervenience relationship, and the physicalist would certainly argue this supervenicience relationship holds true.

Even if we accept however, that the mind naturally supervenes on the brain, we can't say it logically supervenes on the brain. Logical supervenience is a much more stringent requirement, and clearly p-zombies for example, are conceivable. Therefore, we don't generally suggest that the mind is logically supervenient on the brain. Natural supervenience is a subset of logical supervenience.
 
  • #142
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Hi pftest,

You jogged my memory... I remember talking about this now. I think what you're saying is that the supervenience relationship is conceptual in the sense that it depends on the individual who conceives of the relationship. Different individuals will have a different conceptual relationship so the supervenience relationship isn't consistent between individuals. Is that right?

Supervenience can be broken down into logical versus natural supervenience, but supervenience alone means the following:

Ref: http://en.wikipedia.org/wiki/Physicalism#Supervenience

For example, the pressure of a gas in a container supervenes on the temperature, number of molecules that make up the gas, and the volume of the container. The ideal gas law is used for illustration only; PV=nRT. So we can say the pressure supervenes on the physical state of the gas molecules. Without a change to the physical state of the gas molecules, we can’t get a change in the pressure. If we change one of the gas's properties, such as temperature, the pressure will also change. In this case, the pressure of the gas "naturally supervenes" on the physical state of the gas molecules. This relationship is given by the ideal gas law, PV=nRT. We might however, conceive of a world where the constant R is different and therefore, a mole of gas at a given temperature and in a given volume would have a pressure DIFFERENT than the pressure we know to exist. So the particular pressure of the gas we measure in our world “naturally supervenes” on the physical state according to our equation but it does not “logically supervene” since the value for R could conceivably be different in a different world.
(See Chalmers, “The Conscious Mind” pg 36)

For philosophy of mind, a physicalist would contend that the mind supervenes on the brain in some way. For the sake of illustration, we might consider a physicalist who would argue that the mind is a higher level phenomena created by the interaction of neurons in the brain. Therefore, the mind supervenes on both these interactions and on the neurons themselves. This is a supervenience relationship, and the physicalist would certainly argue this supervenicience relationship holds true.

Even if we accept however, that the mind naturally supervenes on the brain, we can't say it logically supervenes on the brain. Logical supervenience is a much more stringent requirement, and clearly p-zombies for example, are conceivable. Therefore, we don't generally suggest that the mind is logically supervenient on the brain. Natural supervenience is a subset of logical supervenience.
What i mean when i say supervenience is conceptual, is basically that it isnt known to occur anywhere in the physical world, so it is a purely hypothetical relationship. Perhaps it is like the metaphor of the hardware/software distinction: such a distinction doesnt actually physically exist, but the metaphor is popular in debates about consciousness.


Im glad you picked the gas example because i think it illustrates what i mean.

The higher and lower levels of existence, as mentioned in the wikipedia quote, are actually higher and lower level descriptions. Physically speaking, pressure is reducible to its molecular ingredients (which in turn are reducible to eventually elementary particles and forces). So we humans may describe the system at a higher level and speak of pressure, but physically there is only one level that actually exists. A higher level description merely exists as a mental model in our minds. Physically speaking, the supervenience relationship between pressure and molecule is a "consists of" or better, an " = " relationship. Pressure = its molecules, a rock = its molecules, etc.

So when someone says that mind supervenes on brain, it actually still means mind = brain.
 
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  • #143
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Just a quick example clarifying supervenience:

We have 2 different brains - B1 and B2.

If the mind is identical with the brain these will always produce different mentality (M1 != M2 where B1 = M1 and B2 = M2). // reductive physicalism

If the mind supervene on the brain these can sometimes produce identical mentality (M1 = M2 where B1 -> M1 and B2 -> M2). //non-reductive physicalism

So what do we know from introspection - our qualia changes over time, but we are still able to experience the same qualia sometimes. Let's say the brain state of 5 year old is B1 and this same person's brain state at 40 years is B2. Clearly these 35 years have changed massively the structure of his brain, but this person would be still able to experience and feel the same way as when he was at 5. This is a strong argument supporting supervenience and the multiple realizability. The mind-brain identity supporters can then say that we are mistaken and our memory is deceiving us, so we always experience different mental state, but with very tiny changes, which we can't "catch".
 
  • #144
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Just a quick example clarifying supervenience:

We have 2 different brains - B1 and B2.

If the mind is identical with the brain these will always produce different mentality (M1 != M2 where B1 = M1 and B2 = M2). // reductive physicalism

If the mind supervene on the brain these can sometimes produce identical mentality (M1 = M2 where B1 -> M1 and B2 -> M2). //non-reductive physicalism

So what do we know from introspection - our qualia changes over time, but we are still able to experience the same qualia sometimes. Let's say the brain state of 5 year old is B1 and this same person's brain state at 40 years is B2. Clearly these 35 years have changed massively the structure of his brain, but this person would be still able to experience and feel the same way as when he was at 5. This is a strong argument supporting supervenience and the multiple realizability. The mind-brain identity supporters can then say that we are mistaken and our memory is deceiving us, so we always experience different mental state, but with very tiny changes, which we can't "catch".
You have completely misunderstood supervenience (sorry). The mind supervenes on the brain if two identical brains will produce identical minds. Nothing stops different brains from producing the same mind under supervenience, but it is not part of the definition. No one in their right mind would claim that a 5 year old and 40 year old have the same conscious experience. They may have the same experience of redness, but no two individuals have the same overall experience as a whole.
 
  • #145
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Nothing stops different brains from producing the same mind under supervenience, but it is not part of the definition.
Yes, you are right it's not, but its part of what non-reductive physicalism is.

[Mind-body supervenience] The mental supervenes on the physical in that any two things (objects, events, organisms, persons, etc.) exactly alike in all physical properties cannot differ in respect of mental properties. That is, physical indiscernibility entails psychological indiscernibility.

What you mean by "overall experience as a whole"? Take for example the feeling of surprise. How it feels to be surprised at 5 and at 40? Do you think its different?
 
  • #146
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Yes, you are right it's not, but its part of what non-reductive physicalism is.

[Mind-body supervenience] The mental supervenes on the physical in that any two things (objects, events, organisms, persons, etc.) exactly alike in all physical properties cannot differ in respect of mental properties. That is, physical indiscernibility entails psychological indiscernibility.
Yes but psychological indiscernibility does not entail physical indiscernibility. This means that different brains do not necessarily produce different mental states according to physicalism.

What you mean by "overall experience as a whole"? Take for example the feeling of surprise. How it feels to be surprised at 5 and at 40? Do you think its different?
I mean the total contents of your mental/conscious state at that time. You have qualia such as the experience of redness or the smell of roses which may be largely the same between individuals, but the overall mental state is different. I don't think it is really possible to feel surprised in the same way twice or between two individuals due to the myriad associated mental states which are unique to an individual at that time. One of the most important properties of conscious states is the level of integration, meaning that each component cannot be analysed separately http://en.wikipedia.org/wiki/Integrated_Information_Theory.
 
  • #147
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We don't know if there are any mental states, which are the same for different individuals. We can only guess. That's why I gave the example with the same person at different ages. What I know from introspection is that the same chemicals can cause me different qualia, but I am also able to experience some things the same way, as when I was a kid. That's why the reductive physicalism has serious problems, because according to it, different brain state always produces different mental state.

And IIT is interesting, but we don't know if the mental reduces to information.
 
  • #148
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We don't know if there are any mental states, which are the same for different individuals. We can only guess. That's why I gave the example with the same person at different ages. What I know from introspection is that the same chemicals can cause me different qualia, but I am also able to experience some things the same way, as when I was a kid. That's why the reductive physicalism has serious problems, because according to it, different brain state always produces different mental state.

And IIT is interesting, but we don't know if the mental reduces to information.
That doesn't really appear to be an argument of merit to me. Firstly, you can't say whether you experience things the same way as when you were a kid. Even if you could, it wouldn't be particularly surprising. There are several hierarchies in the brain. One particular sensory experience memory may be contained in a small region of somatic cortex. It's functional organization can be preserved. It (the chunk of somatic cortex) may even have several different physical states over the course of the person's lifetime, yet still produce the same result. Degeneracy and redundancy are fairly common in biological systems (and it makes sense, of course, for such complex machines to keep running in a chaotic environment requires fail-safes, which is what degeneracy brings you).

On the other side of the hierarchy, the representation of self is widely distributed throughout the brain. You can take half of somebody's brain out and they could still feel mostly like themselves (and even mostly recover given enough time). Of course, they're not going to be the same person in totality. Older people, who have reduced plasticity, might never recover (i.e. they will suffer some form of retardation because their brain has already committed regions to particular tasks). Whereas a child who still has a lot of plasticity is likely to fully recover. Because it has plasticity, the system is able to reorganize into a complete set (but now with half the computing power, you might say).
 
  • #149
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That's why the reductive physicalism has serious problems, because according to it, different brain state always produces different mental state.
This not true at all. I don't even agree with physicalism but physicalists do not believe what you say here.
 
  • #150
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Type physicalism (also known as reductive materialism, type identity theory, mind-brain identity theory and identity theory of mind) is a physicalist theory, in philosophy of mind. It asserts that mental events can be grouped into types, and can then be correlated with types of physical events in the brain. For example, one type of mental event like "mental pains" will, presumably, turn out to be describing one type of physical event (like C-fiber firings). [wikipedia]

http://www.iep.utm.edu/identity/#H4 said:
Putnam’s argument can be paraphrased as follows: (1) according to the Mind-Brain Type Identity theorist (at least post-Armstrong), for every mental state there is a unique physical-chemical state of the brain such that a life-form can be in that mental state if and only if it is in that physical state. (2) It seems quite plausible to hold, as an empirical hypothesis, that physically possible life-forms can be in the same mental state without having brains in the same unique physical-chemical state. (3) Therefore, it is highly unlikely that the Mind-Brain Type Identity theorist is correct.
The Multiple Realization Argument said:
Type physicalism says that pain is C-fiber excitation. But that implies that unless an organism has C-fibers or a brain of an appropriate biological structure, it cannot have pain. But aren't there pain-capable organisms, like reptiles and mollusks, with brains very different from the human
brain? Perhaps in these species the neurons that work as nociceptive neurons--pain-sensitive neurons--aren't like human C-fibers at all. Can the type physicalist reply that it should be possible to come up with a more abstract and general physiological description of a brain state common to all organisms, across all species, that are in pain state? This is highly unlikely, but how about inorganic systems? Could there not be intelligent extraterrestrial creatures with a complex and rich mental life, one that is very much like ours, but whose biology is not carbon-based? And isn't it conceivable--in fact, at least nomologically if not practically possible--to build intelligent electromechanical systems (that is, robots) to which we would be willing to attribute various mental states? Moreover, the neural substrates of certain mental functions can differ from person to person and may change over time even in a single individual through maturation, learning, and injuries to the brain. We should keep in mind that if pain is identical with physical state C, then pain is identical with state C not only in actual organisms and systems but in all possible organisms and systems.

These considerations are usually taken to show that any given mental state is "multiply realizable" in a large variety of physical/biological structures, with the consequence that it is not possible to identify a mental state with a physical state. If pain is identical with a physical state, it must be identical with some particular physical state; but there are indefinitely many physical states that can "realize" (or "instantiate," "implement," etc.) pain in all sorts of pain-capable organisms and systems. So pain, as a type of mental state, cannot be a neural-state type or any other physical-state type.

This, in brief, is the influential "multiple realization" argument against type physicalism Hilary Putnam advanced in the late 1960s (we will recur to multiple realization in the next chapter). It had a critical impact on the way philosophy of mind has developed since then: It effectively retired type physicalism as the reigning doctrine on the mind-body problem, throwing the very term "reductionism" into disrepute and ushering in the era of "nonreductive physicalism." Further, it inspired a new conception of mentality, "functionalism," which has been highly influential since the 1970s and which is arguably still the most widely accepted view on the nature of mind.
 

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