When you can't test it and there is no evidence possible (for or against), any answer is arbitrary and subjective.
In case anyone has failed to make the connection, this is also highly relevant to John Searle's Chinese Room thought experiment. It's been answered half a dozen unique ways already, but the best (and easiest) answer has always been this one: how do you prove that humans speak Chinese? In the context of the premises created by Searle's reasoning, you can't. That means if you accept humans do speak Chinese, you must necessarily reject at least one of the premises.
Just to fill it in for those who have never encountered it, this is the formal reasoning of the Chinese Room :
[P1] Programs are formal (syntactic). [P2] Minds have mental contents (semantics). [P3] Syntax by itself is neither constitutive of nor sufficient for semantics.
[C] Programs are neither constitutive of nor sufficient for minds.
To the serious philosophy buffs, this probably looks like one of the dumbest arguments you've ever seen (and it is). It turns out that not one but _two_ of the premises are wrong.
Response to P1: programs can incorporate non-synactic information. In fact, all meaningful programs necessarily include semantics! That there is some underlying bootstrapped meaning being preassigned by the environment is totally irrelevant. All human beings also exist, and have always existed, in an environment which provides the pre-existing meaning to them (this is what we often call culture or society today, but it used to be much more primitive). Try to raise a child in a sterile environment, with absolutely no connection to anything that could convey any meaning. It will either die, or find a way to assign meaning even in its isolation. In the latter case, its understanding and semantics will be COMPLETELY different from that of any normal person raised in our society. This is the proof that semantics is both ultimately arbitrary and imprinted by context, which shouldn't need to have been proven if some pretentious "philosophers" could bother to think first.
Response to P3: The arbitrary division between syntax and semantics is itself mere semantics, and therefore only as meaningful or meaningless as any thinking agent wants it to be. You may claim all you like that mathematics is just symbols and manipulation of symbols, but the fact that they're symbols does not preclude their meaning in any way. Indeed, a proper view of symbol mechanics requires allowing them to be assigned arbitrary meanings. Let's take an extremely famous example just to prove the point here: E = mc^2 . It's a sequence of symbols and some mathematical relations (equality, multiplication, exponentation, and more generally real arithmetic). Surely it has no meaning, right? Actually, it has whatever meaning we give to it. Once given the correct definitions of E as energy, m as mass, and c as the speed of light all of a sudden the equation has great significance. Where did this come from?
It originated from the environmental context. If you had given this exact equation to a tribe of early humans a million years ago, they would not have "understood" anything from it regardless of what form (syntax) you used. That doesn't negate the meaning of the equation in the minds of those who understand it. More generally stated, the subjective viewpoint of some agents that something is meaningless does not remove the subjective meaning behind it for others. Again, this should have been totally obvious to an competent philosopher.
As for the related problem, called symbol grounding, it's trivially solved. Once you assign meanings to symbols which are attached to real, observable, and verifiable objects in the actual world around us, you have "grounded" the symbols into an empirical and rational context. This is very easy to do and actually done in pretty much every computer program ever made, when we assign names to the variables. For an intelligent machine, the naming and contextual information is equally important as the relationships between variables, and is therefore preserved instead of removed by a compiler.
You want an objective way to describe the subjective experience of "green"? That falls into the category of "dumb questions". The sky can be purple in your world, for all anyone cares. It's of no importance.
It should be pretty clear that any sentient machine would observe and experience the world differently from a human, due to its senses and processing hardware being different. That doesn't invalidate its understanding or feelings about the situation at all. Saying that it does is simply prejudice, and it strikes me as bizarre that so few people seem to realize that. (Maybe it shouldn't. People are very quick to dismiss the internal state and subjective experiences of animals as meaningless, no matter how similar they are to us and despite the clear evolutionary link.)
The point that yndrd1984 made which you completely failed to respond to is that if "qualia" is a real and objective entity -- as the fictiona soul is purported to be in every religion that uses it -- then it must be measurable in some way. If it can't be measured, can't be observed, can't be predicted, can't be understood in anything other than wholly arbitrary and personal ways -- then what the hell good is it? It's useless and acts identically to any fictional non-existent entity. If we're allowed to bring random fiction into a discussion in order to derail rationality, then allow me to introduce you to Mixleblizlethorp. You can't prove she doesn't exist!
In any case, the philosopher's qualia is no mystery. It's just another emergent phenomena, much as self-consciousness and intelligence are (the other supposedly elusive human-only traits). When you put the right algorithms together with the right sensors, it will certainly work as well in a machine as it does in a man. It already works, in fact, just not as well. No one seems to care that we have machines which are comparable to the lower animals already. Why is it that they think progress on the problem is going to suddenly stop? Or that this will take centuries to solve? There is no evidence for this view, and plenty of evidence that the systems continue to improve at a brisk pace. The progress in computer vision over the last twenty to thirty years alone has been mind-bogglingly massive. Comparing the present rate of robotics development with the miserably slow rate of human moral development, we are quite likely to have people arguing against personhood rights for machines with those machines themselves.
"Those who say it can't be done should not interrupt those doing it."
There's no reason to believe that an intelligent self-aware machine necessarily turns out to be the Terminator (or the machines in the Matrix, or whatever other Hollywood incarnations you may want to mention). It could, of course, just as any human being could turn out to be a genocidal dictator. There's every reason to think that the environment has a huge influence on whether this actually happens, whether for man or machine.
"We don't need to prove it's deterministic since we a priori know that it must be."
That silence is the sound of a brain not thinking. You are apparently stuck in the mindset of 19th century classical physics, where everything is obviously deterministic and predictable if you have enough information. We've since discovered numerous phenomena -- radioactivity, wave/particle duality, entanglement -- which behave in ways that are indistinguishable from genuine randomness given the best available physics. It's no longer obvious to most fully educated people that the universe is deterministic in the purest (and classical) sense.
There is also the issue of counterfactual definiteness, which is very commonly assumed. Whenever you make a statement, thought experiment, or simulation that begins with something like "if we recreate the previous conditions and run the experiment again", stop. There's no evidence to support the capacity to do that in the real world. Precisely regenerating the exact prior state would require a level of influence bordering on omnipotence. This is very significant to experiments whose causes cannot be described solely in terms of classical mechanics, and is a big part of the reason quantum mechanics manages to confuse so many.
If testing the determinism of the mind were so simple, we'd have done it long ago.
That experiment doesn't work in practice. Take a look at your design: "forbid them any sensory input". Neurons don't actually do very much of anything without sensory input. Depending on how you define the sensory class, they may do absolutely nothing at all. Specifically what aspects of the environment are considered sensory and which aren't? Normally you think of touch or contact as a sensory input, right? So is the neuron's thermal and electrical contact with the surroundings a sensory input? Do we conduct the experiment at absolute zero in a vacuum? (Nothing interesting happens in that one.)
Science is difficult in large part because creating a meaningful experimental design to discover exactly what you wanted is extremely challenging and fraught with potential false steps. Most likely several variations on your experiment have already been run, and they didn't tell us much.
You're mostly right in each respect, but there's more to be said. Claiming that boredom is nondeterminism isn't just appeal to intuition, it's actually begging the question (putting the conclusion into the premises of the argument). The latter is worse, in my view. None of this means that some sorts of boredom couldn't be evidence for nondeterministic behavior, but one has to actually present the case for that rather than simply asserting it.
On the second count, it's not only unknown internal states but unknown external states that can warp our view of reality as to the degree of determinism (or reliability) in something. For instance, there are many devices which will operate perfectly in some environments and fail miserably in others. Often the difference is the degree of randomness in the inputs they face. The fact that they do or do not face unpredictable external challenges is, however, independent to the question of strict determinism.
For the third, it's basically circular reasoning to state it either way. The randomness of quantum mechanical systems (upon which everything exists) doesn't ensure anything about the degree of determinism in emergent systems. This is one of the many unintuitive facts about QM. The classical world that we directly observe is an aggregate of these countless probabilistic events (and the probabilities are allowed to be any real number inclusive from zero to one, where the endpoints are essentially pure determinism). It may seem very weird to some that you can build a very non-random system on a basis that includes unpredictable entropy, but it's how the world really is.
With regard to generating entropy for a machine, there are several reliable sources. You don't necessarily have to use strictly quantum mechanical effects like radioactive decay, tracking electrons, or photon entanglement. It's also possible, for instance, to sample environmental noise in the aggregate. Sampling the noise from one or more radio signals, or the kinetic noise that is present in temperature, works quite well. It's typically much easier to engineer than reliably using the QM effects directly, too.
It's mere semantic games to redefine all random elements of a machine as external inputs that don't count towards its nondeterminism. That same dumb magic trick can be used to show that humans are completely deterministic. Why it is that people have so much trouble grasping this, I'm not sure. Perhaps it's mere egotism.
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When you can't test it and there is no evidence possible (for or against), any answer is arbitrary and subjective.
In case anyone has failed to make the connection, this is also highly relevant to John Searle's Chinese Room thought experiment. It's been answered half a dozen unique ways already, but the best (and easiest) answer has always been this one: how do you prove that humans speak Chinese? In the context of the premises created by Searle's reasoning, you can't. That means if you accept humans do speak Chinese, you must necessarily reject at least one of the premises.
Just to fill it in for those who have never encountered it, this is the formal reasoning of the Chinese Room :
[P1] Programs are formal (syntactic).
[P2] Minds have mental contents (semantics).
[P3] Syntax by itself is neither constitutive of nor sufficient for semantics.
[C] Programs are neither constitutive of nor sufficient for minds.
To the serious philosophy buffs, this probably looks like one of the dumbest arguments you've ever seen (and it is). It turns out that not one but _two_ of the premises are wrong.
Response to P1: programs can incorporate non-synactic information. In fact, all meaningful programs necessarily include semantics! That there is some underlying bootstrapped meaning being preassigned by the environment is totally irrelevant. All human beings also exist, and have always existed, in an environment which provides the pre-existing meaning to them (this is what we often call culture or society today, but it used to be much more primitive). Try to raise a child in a sterile environment, with absolutely no connection to anything that could convey any meaning. It will either die, or find a way to assign meaning even in its isolation. In the latter case, its understanding and semantics will be COMPLETELY different from that of any normal person raised in our society. This is the proof that semantics is both ultimately arbitrary and imprinted by context, which shouldn't need to have been proven if some pretentious "philosophers" could bother to think first.
Response to P3: The arbitrary division between syntax and semantics is itself mere semantics, and therefore only as meaningful or meaningless as any thinking agent wants it to be. You may claim all you like that mathematics is just symbols and manipulation of symbols, but the fact that they're symbols does not preclude their meaning in any way. Indeed, a proper view of symbol mechanics requires allowing them to be assigned arbitrary meanings. Let's take an extremely famous example just to prove the point here: E = mc^2 . It's a sequence of symbols and some mathematical relations (equality, multiplication, exponentation, and more generally real arithmetic). Surely it has no meaning, right? Actually, it has whatever meaning we give to it. Once given the correct definitions of E as energy, m as mass, and c as the speed of light all of a sudden the equation has great significance. Where did this come from?
It originated from the environmental context. If you had given this exact equation to a tribe of early humans a million years ago, they would not have "understood" anything from it regardless of what form (syntax) you used. That doesn't negate the meaning of the equation in the minds of those who understand it. More generally stated, the subjective viewpoint of some agents that something is meaningless does not remove the subjective meaning behind it for others. Again, this should have been totally obvious to an competent philosopher.
As for the related problem, called symbol grounding, it's trivially solved. Once you assign meanings to symbols which are attached to real, observable, and verifiable objects in the actual world around us, you have "grounded" the symbols into an empirical and rational context. This is very easy to do and actually done in pretty much every computer program ever made, when we assign names to the variables. For an intelligent machine, the naming and contextual information is equally important as the relationships between variables, and is therefore preserved instead of removed by a compiler.
You want an objective way to describe the subjective experience of "green"? That falls into the category of "dumb questions". The sky can be purple in your world, for all anyone cares. It's of no importance.
It should be pretty clear that any sentient machine would observe and experience the world differently from a human, due to its senses and processing hardware being different. That doesn't invalidate its understanding or feelings about the situation at all. Saying that it does is simply prejudice, and it strikes me as bizarre that so few people seem to realize that. (Maybe it shouldn't. People are very quick to dismiss the internal state and subjective experiences of animals as meaningless, no matter how similar they are to us and despite the clear evolutionary link.)
The point that yndrd1984 made which you completely failed to respond to is that if "qualia" is a real and objective entity -- as the fictiona soul is purported to be in every religion that uses it -- then it must be measurable in some way. If it can't be measured, can't be observed, can't be predicted, can't be understood in anything other than wholly arbitrary and personal ways -- then what the hell good is it? It's useless and acts identically to any fictional non-existent entity. If we're allowed to bring random fiction into a discussion in order to derail rationality, then allow me to introduce you to Mixleblizlethorp. You can't prove she doesn't exist!
In any case, the philosopher's qualia is no mystery. It's just another emergent phenomena, much as self-consciousness and intelligence are (the other supposedly elusive human-only traits). When you put the right algorithms together with the right sensors, it will certainly work as well in a machine as it does in a man. It already works, in fact, just not as well. No one seems to care that we have machines which are comparable to the lower animals already. Why is it that they think progress on the problem is going to suddenly stop? Or that this will take centuries to solve? There is no evidence for this view, and plenty of evidence that the systems continue to improve at a brisk pace. The progress in computer vision over the last twenty to thirty years alone has been mind-bogglingly massive. Comparing the present rate of robotics development with the miserably slow rate of human moral development, we are quite likely to have people arguing against personhood rights for machines with those machines themselves.
"Those who say it can't be done should not interrupt those doing it."
There's no reason to believe that an intelligent self-aware machine necessarily turns out to be the Terminator (or the machines in the Matrix, or whatever other Hollywood incarnations you may want to mention). It could, of course, just as any human being could turn out to be a genocidal dictator. There's every reason to think that the environment has a huge influence on whether this actually happens, whether for man or machine.
"We don't need to prove it's deterministic since we a priori know that it must be."
That silence is the sound of a brain not thinking. You are apparently stuck in the mindset of 19th century classical physics, where everything is obviously deterministic and predictable if you have enough information. We've since discovered numerous phenomena -- radioactivity, wave/particle duality, entanglement -- which behave in ways that are indistinguishable from genuine randomness given the best available physics. It's no longer obvious to most fully educated people that the universe is deterministic in the purest (and classical) sense.
There is also the issue of counterfactual definiteness, which is very commonly assumed. Whenever you make a statement, thought experiment, or simulation that begins with something like "if we recreate the previous conditions and run the experiment again", stop. There's no evidence to support the capacity to do that in the real world. Precisely regenerating the exact prior state would require a level of influence bordering on omnipotence. This is very significant to experiments whose causes cannot be described solely in terms of classical mechanics, and is a big part of the reason quantum mechanics manages to confuse so many.
If testing the determinism of the mind were so simple, we'd have done it long ago.
That experiment doesn't work in practice. Take a look at your design: "forbid them any sensory input". Neurons don't actually do very much of anything without sensory input. Depending on how you define the sensory class, they may do absolutely nothing at all. Specifically what aspects of the environment are considered sensory and which aren't? Normally you think of touch or contact as a sensory input, right? So is the neuron's thermal and electrical contact with the surroundings a sensory input? Do we conduct the experiment at absolute zero in a vacuum? (Nothing interesting happens in that one.)
Science is difficult in large part because creating a meaningful experimental design to discover exactly what you wanted is extremely challenging and fraught with potential false steps. Most likely several variations on your experiment have already been run, and they didn't tell us much.
You're mostly right in each respect, but there's more to be said. Claiming that boredom is nondeterminism isn't just appeal to intuition, it's actually begging the question (putting the conclusion into the premises of the argument). The latter is worse, in my view. None of this means that some sorts of boredom couldn't be evidence for nondeterministic behavior, but one has to actually present the case for that rather than simply asserting it.
On the second count, it's not only unknown internal states but unknown external states that can warp our view of reality as to the degree of determinism (or reliability) in something. For instance, there are many devices which will operate perfectly in some environments and fail miserably in others. Often the difference is the degree of randomness in the inputs they face. The fact that they do or do not face unpredictable external challenges is, however, independent to the question of strict determinism.
For the third, it's basically circular reasoning to state it either way. The randomness of quantum mechanical systems (upon which everything exists) doesn't ensure anything about the degree of determinism in emergent systems. This is one of the many unintuitive facts about QM. The classical world that we directly observe is an aggregate of these countless probabilistic events (and the probabilities are allowed to be any real number inclusive from zero to one, where the endpoints are essentially pure determinism). It may seem very weird to some that you can build a very non-random system on a basis that includes unpredictable entropy, but it's how the world really is.
With regard to generating entropy for a machine, there are several reliable sources. You don't necessarily have to use strictly quantum mechanical effects like radioactive decay, tracking electrons, or photon entanglement. It's also possible, for instance, to sample environmental noise in the aggregate. Sampling the noise from one or more radio signals, or the kinetic noise that is present in temperature, works quite well. It's typically much easier to engineer than reliably using the QM effects directly, too.
It's mere semantic games to redefine all random elements of a machine as external inputs that don't count towards its nondeterminism. That same dumb magic trick can be used to show that humans are completely deterministic. Why it is that people have so much trouble grasping this, I'm not sure. Perhaps it's mere egotism.