How physicists handle the idea of Free Will?

[pftest]

Hi pftest,

Sounds like you're suggesting mental states* influence physical states* and also rejecting the causal closure of the physical. Would you say that we need to reject causal closure to make any sense of free will, and if so, why - what argument do you find persuasive?

*Here I'm using the terms mental states and physical states as Kim uses them.

I think mental states influence physical states yes. It may be tempting to deny causal powers to consciousness, and that it may seem like it saves the day for physicalism. However, i say the opposite is true and it would actually be completely selfdestructive for physicalism.

Personally i do not believe the physical is causally closed, but it is possible for it to be causally closed while at the same time also allowing mental causation. This is possible if the two are identical.

 

[sophiecentaur]

I meant that they 'explain' what they feel in terms of 'consciousness' IF they actually stop to think about it at all. It seems to me that it's a very similar thing to having a god sort of concept. Faith if you like but what is that in the end?

 

[Goodison_Lad]

I meant that they 'explain' what they feel in terms of 'consciousness' IF they actually stop to think about it at all. It seems to me that it's a very similar thing to having a god sort of concept. Faith if you like but what is that in the end?

I'm not very familar with the examples you must have encountered, but certainly, if consciousness is offered as an explanation, and that's it, it's completely unsatisfactory because it is no explanation at all, just another set of problems.

It strikes me that this thread, and similar ones, exists in the first place because people feel the have free will, whether they're right to or not. If free will doesn't exist then the feeling of it being real is worth as much consideration as the question of whether it exists.

 

[pftest]

Is it a chance that we can do e.g. math only when we're awake and conscious or there is something more profound to be understood. There are some "intelligent" activities like reading, writing, doing math that seems to be incompatible with an unconscious state of mind.

Yes, what does consciousness achieve physically that cannot be achieved by nonconscious physical processes? I think we must conclude that consciousness is necessary for at least some physical processes to occur. But if we do so, then it will imply that consciousness is required for far more than just what happens in brains, since physically speaking what happens in our brains isn't very different from what happens in other physical objects.

 

[John Creighto]

As possible a-side. Many often think of the macroscopic world as if it is determined by the random motion of particles but the very fact that the macroscopic particles are organized into structures and systems poses constraints and order upon the behavior of the microscopic world.

Microscopic motion is thought of as stochastic. Particles randomly collide with each or are detected with complete uncertainty based on some quantum function. However, these microscopic particles are not acting in a world devoid of structure. There are fields, even wave phenomena is a form of macroscopic organization.

We as a system are to a degree independent of our environment in that our behavior is as much determined by what is internal to us as what is external to us.

This of course doesn’t address the question of consciousness but someone mentioned sleep walking. One thing that distinguishes this from conscious daytime action is that we remember things in the day time and we perhaps reflect on what we do more deeply.

Thus consciousness must at least in part consist of reflecting on sense data and remembering the results in an organized (probably chronologically) fashion so that through some combination of reason and memory we can make better choices in the future.

 

[madness]

Yes, what does consciousness achieve physically that cannot be achieved by nonconscious physical processes? I think we must conclude that consciousness is necessary for at least some physical processes to occur.

Or that consciousness inevitably arises during certain processes. We don't know that consciousness actually does anything, it may just be a biproduct or epiphenomenon associated with certain physical processes.

 

[Pythagorean]

I'm not very familar with the examples you must have encountered, but certainly, if consciousness is offered as an explanation, and that's it, it's completely unsatisfactory because it is no explanation at all, just another set of problems.

It strikes me that this thread, and similar ones, exists in the first place because people feel the have free will, whether they're right to or not. If free will doesn't exist then the feeling of it being real is worth as much consideration as the question of whether it exists.

unless the feeling is just a spandrel
http://en.wikipedia.org/wiki/Spandrel_(biology )

 

[madness]

unless the feeling is just a spandrel
http://en.wikipedia.org/wiki/Spandrel_(biology )

Why should that make the feeling of freewill not worth consideration? I think that is exactly the point - the feeling of freewill exists, and that is what we can study scientifically. This is what I was getting at when I was discussing the sense of agency.

 

[Goodison_Lad]

unless the feeling is just a spandrel
http://en.wikipedia.org/wiki/Spandrel_(biology )

Well, suppose we agree for now that the feeling that we have free will is worth consideration, unless it is a spandrel.

The question is: is it possible to ascertain whether it is a spandrel, so that we don't need to bother with it if does turn out to be one?

 

[Deicider]

Didn't really read the thread so this post is to the point of why free will is nonsensical.

Free will is an impossible concept.
Because either all physical interactions are pure random or determined there can't be no -what you call- "free will".

If they are all determined then the outcome is fixed, if its random then its not 'will' of any kind, just randomness.
People justifying "free will" using examples like self sacrifice are poorly educated individuals, just open any evolutionary biology book and you will understand why someone makes seemingly unreasonable choices.

The only shelter "free will" can take is dualism ( a.k.a. magic).
Dunno why but almost everyone can't see the obvious, that even if god existed he would be deterministic, because any kind of pattern implies laws/rules, otherwise it wouldn't be a pattern.

That means even if something magical existed "outside" of physical reality that cause consciousness, that too would be deterministic, because it would have a purpose, a structure, a pattern, it would be just another type of physics.

Free will is not something "unlikely" or "wrong" its plainly stupid.

The only type of free will we have is the causal one, like picking which ice cream flavor we eat, chocolate or vanilla?
Our wiring, and all other physical interactions brings you into a "choice", that is the only acceptable form of will."TemplarKnightOfStuffTemperature", if you seen this before then you should be embarrassed.

 

[John Creighto]

That means even if something magical existed "outside" of physical reality that cause consciousness, that too would be deterministic, because it would have a purpose, a structure, a pattern, it would be just another type of physics.

I can't help think that it is tautological to try to define something that exists outside of reality from within reality.
Gödel's theorem says:
“A meaningful axiomatic system cannot be shown to be both consistent and complete except by using axioms from outside that system. Those additional axioms must come from a system that logically encompasses the system under study.”
http://www.sexandphilosophy.co.uk/pe09_axioms_of_evolution.htm
Aristotle thought the first cause should be from something which is un-perishable.
So if there is a first cause, and it is possible for us to prove (or at least understand) we must find laws of physics which don't break down at the beginning of time. The other possibility is that there is a larger system of which our universe is contained within but we cannot see the whole picture (hidden variables) and consequently cannot discover all of its laws. Plato's allegory of the cave is a good metaphor to describe this.

Determinism is one law of nature we perceive in this world but it is temporal in that it rests on the principle of cause and effect. If tachyons existed what would that do to our notion of cause and effect. We presume that all information travels forward in time but even time is not an absolute quantity. Relativity tells us that even the sequence of events depends on the observer.


Still though from all reference frames we are left with causality being forward in time and hence the possibility of determinism. Well, the notion of cause gives us comfort we know that in complex systems there is never a single cause and at quantum scale systems everything is to a degree random and uncertain.

Everything I said though does not suggest a notion of free will but where did it all begin. Was all the information needed to create everything we see today encoded in the big bang or are we where we are today purely by chance. Whatever part chance played there had to be enough order for complex systems to form. Even if chance played a part in creating what we see today there still needed to be enough rules (cause and effect) for the complexity and order we see today to be a likely outcome. For by chance a lone it would not be possible for such complexity and order to evolve to a scale which gives the appearance of having properties which transcend the physical nature of the universe -- as our notions of free will and consciousness appear to transcend what we perceive as material. What a paradoxical outcome from such an apparently disordered beginning.

If the universe is defined by the laws of physics and it was through these laws of physics from which we evolved -- then as Aristotle would ask, did these laws always exist? For if time is linear and cause and effect always follow the arrow of time then either they always existed, or they originated from some other principles. He would then ask what caused these other principles, or as Atheists ask today, "Who created God"? If cause and effect is an un-perishable principle and always forward in time then either for each event there is always a prior cause or there is a first cause but does the notion of first cause even make sense. Did time exist before the universe and if not there could be no notion of cause before time.

Our perception of time consists of how our memory relates to cause and effect. Without memory we would have no concept of time. Without a concept of time we would have no notion of a cause. All quantum scale dynamics need macro scale order to impose structure. It is only from the perspective of the macroscopic which the laws of the microscopic can be observed but without a frame of reference to observe some order in what sense would such notions as cause exist?

 

[pftest]

Or that consciousness inevitably arises during certain processes. We don't know that consciousness actually does anything, it may just be a biproduct or epiphenomenon associated with certain physical processes.

The problem i see with the idea that consciousness cannot influence anything, is that nothing can influence consciousness either. I would compare it with kicking a ball. You can't kick a ball away without it touching your foot also.

 

[pftest]

About the causal closure of physics: isn't this a necessary consequence of math? The only options it offers are deterministic or random processes. The idea of something being caused by a conscious force (will) is ruled out a priori. The idea of causal closure then depends on the assumption that everything can be described by math. Is this a reasonable assumption?

 

[madness]

The problem i see with the idea that consciousness cannot influence anything, is that nothing can influence consciousness either. I would compare it with kicking a ball. You can't kick a ball away without it touching your foot also.

If consciousness is an epiphenomenon then it is completely determined by the physical and hence is influenced in the strongest possible sense by physical processes. I have no idea what you mean when you say that physical processes cannot influence consciousness.

 

[pftest]

If consciousness is an epiphenomenon then it is completely determined by the physical and hence is influenced in the strongest possible sense by physical processes. I have no idea what you mean when you say that physical processes cannot influence consciousness.

When you say "C is determined by the physical" do you mean "C is physical"? In that case, the causal powers of C are identical to the causal powers of the physical, and it is not an epiphenomenon.

If you do not mean that C is physical, then i don't understand how the physical can influence C, but C cannot influence the physical. Or going back to the ball metaphor: how can a ball can be kicked without it touching the thing that is kicking it?

 

[John Creighto]

The problem i see with the idea that consciousness cannot influence anything, is that nothing can influence consciousness either. I would compare it with kicking a ball. You can't kick a ball away without it touching your foot also.

When I think, doesn’t it change the state of the atoms inside my head? Therefore, don’t my thoughts directly influence at least a small part of the physical world? Therefore, the dynamics of particles depends on how particles are organized in the whole.

We might say though that I have cause backwards. However, the motion of these particles is dependent on fields. Fields are the result of how particles are organized. Well, in theory we may suspect that fields can be modeled as a consequential sum of the totality of particle effects. However, the calculation of such fields is not as interesting as the structure of the fields. It is structure which is the most important property of the whole.

There is a duality between the whole influencing the small and the small influencing the whole. A wave for instance is a macroscopic property. It extends though all space but a single particle can be described as a super position of waves.

The wave isn’t just an emergent property of the particles as even the motion of a single particle is described by a wave. Thus the large and the small are inextricably linked.

The mind is a property of the large and it’s properties are inextricably linked to the states of the particles within our body. Therefore, motion of particles in some regards is influenced by our thoughts. Thus in some way our thoughts influence the small. If thought is equivalent to consciousness then we should also expect consciousness to directly influence the dynamics of particles. If consciousness is not equivalent to thought then what is it?

 

[Ferris_bg]

Here are the four standard models of mind-body interaction.

The mind is a property of the large and it’s properties are inextricably linked to the states of the particles within our body. Therefore, motion of particles in some regards is influenced by our thoughts.

If we accept that the mind is a property of the whole, then as you say at first it seems logical that the mind influences the whole. There is a however one problem with this assumption and its well illustrated by the Supervenience Argument from Kim. The argument points out that the non-reductive physicalism theories entail epiphenomenalism. If the mind supervenes on the physical, then it should be casually inert, if we accept that this is not a case of causal over-determination.

Consciousness is equivalent to intentional/cognitive properties ("thought" as you say) plus qualitative properties of consciousness (qualia) or C = M + Q. C is also unified, meaning that you can't separate M from Q or vice versa.

 

[sophiecentaur]

When we examine our mind, we are a system trying to analyse itself. We are bound to fail to come up with a complete explanation.
I commented earlier that consciousness and 'god' (/faith) are very similar. My thought is that our consciousness is probably closely associated with the need for a complicated organism to communicate with other individuals (huge evolutionary advantage). When we 'consider' a problem in our minds, we use our consciousness to 'discuss' the matter with ourselves rather like we would discuss with someone else. To communicate anything to another person, we often need to express it via our consciousness in order to assemble the words etc.. There are, of course, forms of communication between individuals which are not conscious - as there are between humans and other animals and between other animals. The message is then unstated and 'non-conscious' but it is not an 'intellectual' message that is passed.

 

[ThomasT]

I have always been quite curious how physicists reconcile the concept free will with the determinism of physics.

The term free will is commonly used to refer to at least two things. One is that we obviously consider alternative courses of action. This isn't incompatible with determinsim. The other is that our actions could have, given identical antecedent conditions, resulted in different consequences -- or that, given identical antecedent conditions, we could have thought and acted differently than what we did. This is incompatible with determinism, and amounts to an assumption that our universe is evolving indeterministically.

By determinism I mean the one at macroscopic level, because I know that at quantum level most of the things are based on probabilities. So there's no free will for an electron.

There's no known quantum level of events. There's only, as far as can be objectively known and unambiguously communicated, a macroscopic level of events. The indeterminism of quantum experimental events is realized at the macroscopic level -- the level of instrumental behavior amenable to our sensory apprehension.

But, at macroscopic level, everything seems to have some equation that determines its future, even if that's chaotic and very difficult (for us) to predict.

Not so wrt the macroscopic apprehension of quantum experimental events. Radioactive decay is random, unpredictable. Does that mean that nature is fundamentally indeterministic? Not necessarily. There's just no way to ascertain it one way or the other.

... if I'm to believe in physics determinism, I should give up on the concept of free will ...

Not necessarily. As noted above. I believe in, currently assume, a fundamental deterministic evolution of our universe, but I also think that the term free will has a certain meaning compatible with that assumption.

So how do physicists answer that dilemma - is there free will in physics?

It isn't necessarily a dilemma. It just depends on how the term is defined. Ie., one can assume a fundamental determinism (and there seems to be compelling evidence for this assumption), while still entertaining a connotation of the term free will that's compatible with that assumption. Ie., our choices and actions are causally linked to certain subsequent events.

One conception, phrasing, of free will is that you could have, given identical antecedent events, chosen/done otherwise. The problem with assuming this is that there's absolutely no evidence for it. All that's known is a certain set of antecedent conditions, a certain subsequent set of actions, and a certain subsequent set of conditions -- all of which is compatible with the assumption of a fundamental determinism.

Bottom line -- our universe doesn't appear, taking into account all observational evidence, to be evolving indeterministically. So, a fundamental determinism is assumed, which is compatible with a certain connotation of the term, free will.

 

[sophiecentaur]

People bandy around the term 'free will' but I doubt that anyone could genuinely quote an instance where they were aware of actually having made a purely mental decision (genuinely used their free will) and could describe how they got there. When you actually HAVE made a 'decision' then you start to rationalise it post hoc. On another day, you'd quite possibly come to the exact opposite decision. The term 'free will' is not unlike the term 'democracy'. In both cases the individual has some sort of mis-guided notion that they can actually affect what happens to them. We are at the mercy of Politicians, our pasts and our hormones (all 'random' and powerful influences on what we like to call our free choices.
The only decisions / conclusions that you can arrive at, ante hoc, are the conclusions that arrive from a mathematical process, which is repeatable again and again.
But Maths is neither like our brains nor the Physical World. It is based on axioms.
This thread can never go anywhere because people are trying to relate the nature of the Universe (deterministic or otherwise) to the detailed functioning of their brains (to a depth that has fundamental limits).

 

[madness]

When you say "C is determined by the physical" do you mean "C is physical"? In that case, the causal powers of C are identical to the causal powers of the physical, and it is not an epiphenomenon.

If you do not mean that C is physical, then i don't understand how the physical can influence C, but C cannot influence the physical. Or going back to the ball metaphor: how can a ball can be kicked without it touching the thing that is kicking it?

I mean that in our universe, every identical physical setup will lead to an identical instantiation of consciousness. In philosophical jargon, this means that consciousness naturally supervenes on the physical. However, since it is conceivable that we could have lived in a universe in which these same physical processes lead to a different conscious experience (e.g. we see red as blue and blue as red), we see that consciousness and physical processes are not logically identical.

 

[Ferris_bg]

That sounds like the Zombie argument from Chalmers, but I don't like it and to be more precise, the word "conceive" in it.

 

[madness]

That sounds like the Zombie argument from Chalmers, but I don't like it and to be more precise, the word "conceive" in it.

Well unfortunately, the arguments for physicalism (materialism) come from the same notion of supervenience, which is based on "possible worlds" or "conceivable worlds". It's not something you can get around if you are looking at philosophical debates of this kind.

 

[pftest]

I mean that in our universe, every identical physical setup will lead to an identical instantiation of consciousness. In philosophical jargon, this means that consciousness naturally supervenes on the physical. However, since it is conceivable that we could have lived in a universe in which these same physical processes lead to a different conscious experience (e.g. we see red as blue and blue as red), we see that consciousness and physical processes are not logically identical.

About the supervenience: isn't that how all physical things work? If two riverbeds have an identical setup, the water will flow through them identically. If two planets are identical, the spacetime will be distorted identically. If two computers are identical, the current will flow through them identically. Etc. In all those instances, there is causal interaction between the system and that which supervenes (riverbed <> water, planet <> spacetime), and there is no epiphenomenon.

 

[sophiecentaur]

So how does this relate freedom to make a decision totally independently of the 'Physical' world? What do we mean by 'free will' (the most important word in the title of this thread)? If free will is just an illusion - a view that I tend to favour - then it is generated by the mind as a strategy for marshalling an incomprehensible amount of processes that are going on below the surface. These processes are subject to the same influences that are studied in Science but involve many more variables that are discussed in Physics. In the Physics of large numbers (gas laws and QM) the number of variables are much fewer than are involved in the functioning of the Mind and those situations are all dealt with statistically. In the study of the Mind, we have to use the same level of description that our consciousness uses, of course. This is, necessarily, very approximate and superficial - which is how I see a lot of 'Philosophy' working, being propped up by a set of axioms rather than data. Fair enough and very good fun - but is it really anything more?
This may be difficult for people to accept because it turns us more into automatons than perhaps we would like to be. But that explanation doesn't particularly have to interfere with enjoyment of life and appreciation of all the finer things. It just puts things into perspective.

 

[madness]

About the supervenience: isn't that how all physical things work? If two riverbeds have an identical setup, the water will flow through them identically. If two planets are identical, the spacetime will be distorted identically. If two computers are identical, the current will flow through them identically. Etc. In all those instances, there is causal interaction between the system and that which supervenes (riverbed <> water, planet <> spacetime), and there is no epiphenomenon.

The point is to make the distinction between logical and natural supervenience, and to argue that consciousness supervenes naturally but not logically on physical processes. If something is logically reducible to physical processes, then it is in some sense reducible to or identical to those physical processes. If something is naturally supervenience then they are conceptually distinct entities which seem to coincide in our universe.

I think you may have misunderstood supervenience. Riverbed <> water is not an example of supervenience. H20 <> river is a better example, which would count as logical supervenience.

 

[Pythagorean]

Show me a river that's exactly identical to another river. Unique pattern generation isn't unique to humans.

since it is conceivable that we could have lived in a universe in which these same physical processes lead to a different conscious experience

It could also be that different physical processes can lead to (more or less) the same conscious experience. And in fact, they do at the molecular level. Changing concentration slightly in some local part of the brain would go unnoticed. In most cases, the systems would perform as normal. You already don't attend consciously to much of the plasticity occurring in your CNS right now.

Of course, taking half your brain out or something dramatic like that comes with consequences, but most people still "feel" like the same person, even though they may feel different about themselves. It's not like they lose complete memory of who they are.

http://en.wikipedia.org/wiki/Hemispherectomy#Results

Consciousness is an ill-defined problem. It depends on where you set all the ranges of the parameters of the set of observables that you consider to be consciousness. It's difficulty for us to intuitively understand high-dimensional objects.

It's obviously very difficult to measure subjective experience (which is where some people narrow their definition of consciousness to: the phenomenology), but people attempt other observable measurements.

http://en.wikipedia.org/wiki/Big_Five_personality_traits
http://en.wikipedia.org/wiki/Intelligence_quotient
http://en.wikipedia.org/wiki/Graduate_Record_Examinations

In most social structures, many different members of society can fit the same role, where some social aspect of their personality is defined by the social vacuum they filled, not some internal emergent property.

 

[madness]

Show me a river that's exactly identical to another river. Unique pattern generation isn't unique to humans.



It could also be that different physical processes can lead to (more or less) the same conscious experience. And in fact, they do at the molecular level. Changing concentration slightly in some local part of the brain would go unnoticed. In most cases, the systems would perform as normal. You already don't attend consciously to much of the plasticity occurring in your CNS right now.

Of course, taking half your brain out or something dramatic like that comes with consequences, but most people still "feel" like the same person, even though they may feel different about themselves. It's not like they lose complete memory of who they are.

http://en.wikipedia.org/wiki/Hemispherectomy#Results

Consciousness is an ill-defined problem. It depends on where you set all the ranges of the parameters of the set of observables that you consider to be consciousness. It's difficulty for us to intuitively understand high-dimensional objects.

It's obviously very difficult to measure subjective experience (which is where some people narrow their definition of consciousness to: the phenomenology), but people attempt other observable measurements.

http://en.wikipedia.org/wiki/Big_Five_personality_traits
http://en.wikipedia.org/wiki/Intelligence_quotient
http://en.wikipedia.org/wiki/Graduate_Record_Examinations

In most social structures, many different members of society can fit the same role, where some social aspect of their personality is defined by the social vacuum they filled, not some internal emergent property.

I'm not sure if you are trying to argue against what I have been saying because I don't particularly disagree with anything you wrote here. I don't really see how it fits in with what I have been saying. Supervenience doesn't imply a bijection between the base and supervenient properties it just implies that the supervenient properties are somehow entailed in the base properties.

 

[Pythagorean]

not at all meant to be a dispute; just another consideration.

 

[Goodison_Lad]

If consciousness is not equivalent to thought then what is it?

Good question. Is it possible to be conscious without thought? I think it is - we can be conscious of our thoughts, as we can be conscious of periods when there are no thoughts at all. This view would suggest that consciouness and thought processes are not the same thing, even though they occur in the same arena and usually together.

Consciousness is an ill-defined problem. It depends on where you set all the ranges of the parameters of the set of observables that you consider to be consciousness.

Very true. Should a computer pass the the Turing Test to everyone's satisfaction, there could be little doubt that what it was doing was functionally indistiguishable from thought. If this observable is taken to be a key indicator of consciousness, then the computer could reasonably be considered conscious. But I think many observables people suggest are more linked to thinking rather than the conscious experience.

The rather unsettling conclusion that must be accepted if you subscribe to the view that there is no such thing as genuine free will is that there can be no such thing as responsibility for your actions. If free will is an illusion, so is personal responsibility - your actions are the result of the laws of nature in operation, no matter how inscrutable the processes are. So, as an automaton, I cannot reasonably be held to account any more than I can put a computer on trial for some perceived misconduct. I may in practice be held to account - but it wouldn't be reasonable to expect me to have behaved any differently.

And a whole buch of other cherished notions would also be illusory e.g. merit. We already accept that it's silly, really, to praise somebody for how good-looking, tall, intelligent they are because they had nothing to do with it, yet we believe they had some control over their work-rate, generosity and so on.

Just because these are unpleasant conclusions doesn't mean they're not true. But I happen not believe in the existence of so many illusions.

 

[Pythagorean]

I don't agree. You're still accountable. And the other members of your organismal ensemble will make sure of it... in a deterministic matter.

 

[sophiecentaur]

It strikes me that the term 'supervenience', in this context, is just a way of implying a connection that is not necessarily there. Just because 'we make a decision' - which can obviously affect the way that the molecules of the World behave - does not imply anything at all about any 'supremacy' of that decision over the World. That decision can have easily arisen from the random arrangement of some of the atoms in our brains. Assigning any free action of the mind to make this decision and subsequent action is a massive assumption and not justifiable imho. The reason that you think you made a totally thought-out and independent decision need only be because your mind has developed to give you that impression. It is easy to see that some sort of evolutionary advantage could have turned us out in this way.

 

[pftest]

The point is to make the distinction between logical and natural supervenience, and to argue that consciousness supervenes naturally but not logically on physical processes. If something is logically reducible to physical processes, then it is in some sense reducible to or identical to those physical processes. If something is naturally supervenience then they are conceptually distinct entities which seem to coincide in our universe.

I think you may have misunderstood supervenience. Riverbed <> water is not an example of supervenience. H20 <> river is a better example, which would count as logical supervenience.

But the thing is that "logical supervenience" is a mental construct. It has no physical meaning. This is not a useful concept for the actual physical relationship between consciousness and the brain.

 

[Q_Goest]

Hi pftest,

But the thing is that "logical supervenience" is a mental construct. It has no physical meaning. This is not a useful concept for the actual physical relationship between consciousness and the brain.

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:

"Logical" supervenience (loosely, "possibility") is also a stricter variant of supervenience: some systems could exist in another world (are "logically" possible), but do not exist in our world (are "naturally" impossible). Elephants with wings are logically possible, but not naturally possible. Systems that are naturally possible are also logically possible, but not viceversa. For example, any situation that violates the laws of nature is logically possible but not naturally possible. Natural supervenience occurs when two sets of properties are systematically and precisely correlated in the natural world. Logical supervenience implies natural supervenience, but not viceversa. In other words, there may be worlds in which two properties are not related the way they are in our world, and therefore two naturally supervenient systems may not be logically supervenient.

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.

 

[Goodison_Lad]

I don't agree. You're still accountable. And the other members of your organismal ensemble will make sure of it... in a deterministic matter.

Legal systems are based on the assumption that free will does exist and that people, generally, are not operating merely deterministically. People are considered to have genuine choice, not just the illusion of it, and the main reason prosecutions occur in the first place is that the accused are believed to have exercised said free will in a way the law disapproves of. It is the very notion of free will that underpins the concept of responsibility, and so people are accordingly held responsible for the consequences of their free choices (an expression which is tautological - what meaningful sense could be made of the idea of a ‘non-free choice’?)

The basis for mitigation is where it judged that free will has been significantly compromised, perhaps to the extent that it was completely absent – mental illness, intellectual impairment, duress etc. Society considers that responsibility and free will are two inseparable sides of the same coin.

So I really don’t think we can have it both ways on this point: we have to be consistent. If our actions are deterministic, we can no more be responsible for them than can a dog for barking, a brick for falling or a supernova for exploding. The fact that other automata might act as though they believe I can be held responsible is simply a further manifestation of their delusion. If they were to fully adopt the view that my behaviour is deterministic, and therefore a direct product of effects immune to non-deterministic intervention, they would have to conclude that the concept of responsibility is a redundant one. We might like it, but it is not logically justified.

However, even if the automata of society were to acknowledge that I had no real free choice, this would not mean that they should necessarily act differently. The imposition of a legal code on an automaton might have the effect of being another deterministic factor affecting its future behaviour.

If responsibility does exist without free will we’d have to consider the possibility of extending the legal system so that we could prosecute animals. Am I any the less a victim of determinism than a pigeon?