How did consciousness become a hot interest for physicists & the physical sciences?

[C C]

--> How exactly did consciousness become a problem? And why, after years off the table, is it a hot research subject now?

EXCERPT: [...] Yet, as some philosophers of the early 20th century began to point out, physicalism contains a logical flaw. If consciousness is a secondary byproduct of physical laws, and if those laws are causally closed – meaning that everything in the world is explained by them (as physicalists claim) – then consciousness becomes truly irrelevant. Physicalism further allows us to imagine a world without consciousness, a ‘zombie world’ that looks exactly like our own, peopled with beings who act exactly like us but aren’t conscious. Such zombies have no feelings, emotions or subjective experience; they live lives without qualia. As Chalmers has noted, there is literally nothing it is like to be zombie. And if zombies can exist in the physicalist account of the world, then, according to Chalmers, that account can’t be a complete description of our world, where feelings do exist [...]

Medieval theologians did not sit around debating the ontological status of zombies. They knew for a fact that humans are conscious and built a system of control and punishment around this principle. [...] Torture was a method of mind control premised on a worldview in which conscious minds are morally accountable. Zombies, by contrast, have no real minds and no moral compass: they are neither good nor bad. Since they don’t feel pain in any meaningful sense, torturing a zombie would be pointless. What makes them such formidable foes on screen is that zombies are beyond the limits of subjectivity. We don’t feel for them because they don’t feel. Robots belong to the same order of being. Only when we think bots are developing consciousness (as in Blade Runner and Ex Machina) does our treatment of them become an issue.

[...] Although full-blown materialism (an early variant of physicalism), wasn’t articulated until the 18th century, its shadow was already hovering in Galileo’s 17th-century distinction between objective and subjective qualities. In his book "The Assayer" (1623), Galileo wrote: ‘If ears, tongues, and noses were removed, I am of the opinion that shape, quantity and motion would remain, but there would be an end of smells, tastes, and sounds.’ Shape, quantity and motion – these were not only the objects of science, they were the primary reality. [...] Galileo wrestled with the question of what a new science could be and what aspects of reality such a science could describe. [...] In The Assayer, he wrote: ‘Concerning sensation and things that pertain to it, I claim to understand but little. Therefore I leave it unsaid.’

For most of the history of modern science, subjectivity has been left unsaid – a topic hovering beyond the reach of equations and test-tubes. Why then has it now sprung so strongly to the forefront of scientific thinking? Physicists and chemists might not have been thinking much about subjectivity during the 18th and 19th centuries, however lots of other people were. [...]

But perhaps most surprisingly, just when the ‘stream of consciousness’ was entering our lexicon, physicists began to realise that consciousness might after all be critical to their own descriptions of the world. With the advent of quantum mechanics they found that, in order to make sense of what their theories were saying about the subatomic world, they had to posit that the scientist-observer was actively involved in constructing reality. [...]

Such a view appalled many physicists, who fought desperately to find a way out, and for much of the 20th century it still seemed possible to imagine that, somehow, subjectivity could be squeezed out of the frame, leaving a purely objective description of the world. Albert Einstein was in this camp, but his position hasn’t panned out. Forty years ago, the American theoretical physicist John Wheeler proposed a series of thought experiments to test if an observer could affect whether light behaved as a particle or a wave and, in 2007, the French physicist Alain Aspect proved that they could. Just this April, Nature Physics reported on a set of experiments showing a similar effect using helium atoms. Andrew Truscott, the Australian scientist who spearheaded the helium work, noted in Physics Today that ‘99.999 per cent of physicists would say that the measurement… brings the observable into reality’. In other words, human subjectivity is drawing forth the world.

Not all physicists are willing to go down this path, however, and there is indeed now a growing backlash against subjectivity. That has brought into being the so-called ‘many worlds interpretation’ (MWI) of quantum theory. According to this interpretation, every time a subatomic particle is confronted with options – does it do X, or does it do Y? – the Universe splits into two identical copies of itself, in one of which the particle does X and in the other it does Y. Given that physicists estimate that there are around 10^80 subatomic particles in our Universe, and most of them are confronted with options many times a second, it means that, according to MWI, gazillions of copies of our universe are sprouting off one another every nanosecond.

This fissiparous seething is one of the few ways to interpret quantum behaviour without awarding consciousness a central role, and when I was a physics student the MWI was widely seen as a fringe concept. Today, it is becoming mainstream, in large part because the pesky problem of consciousness simply hasn’t gone away.

Some physicists want to be rid of the problem of consciousness altogether, while others are attempting to treat it as a core material phenomenon. Max Tegmark, a theoretical physicist at the Massachusetts Institute of Technology, for example, hopes that consciousness will turn out to be another state of matter, like a solid, liquid or gas, and he’s calling for physicists to begin exploring the ‘physical correlates of consciousness’. What, he asks, are the physical conditions that pertain when consciousness is present? There are parallel moves in neuroscience to determine the ‘neural correlates of consciousness’ (NCC) – the neurological signatures of awareness. [...]

This is all thrilling science, yet a question remains: will any of it explain subjective experience? Chalmers, the philosopher [formerly a scientist], claims that the problem of experience is not mechanistically reducible and he argues that it will ‘persist even when the performance of all the relevant functions is explained’. In other words, he says, no amount of detail about neuronal potentials and interconnection is going to get us to the essence of subjectivity.

Plenty of neuroscientists, physicists and philosophers disagree with him [...] Giulio Tononi’s book Phi (2012) asks the question: ‘How could mere matter generate mind?’ As a neuroscientist, Tononi says this is a mystery ‘stranger than immaculate conception… an impossibility that defie[s] belief’. Nonetheless, he offers us an explanation of consciousness grounded in information theory that has been admired by both Tegmark and Koch. He wants to do for psychic phenomena what Descartes, Galileo and their heirs did for physical phenomena: he wants to explain subjective experience by generalised empirical rules, and he tells us that such experiences have shapes in a multidimensional mathematical space.

Personally, I don’t have a problem with the idea that subjective experiences might have mathematical correlates any more than Father Coyne minds the notion of neural correlates. As an admirer of co-ordinate geometry, I like Tononi’s concept; at the same time, I don’t accept information theory as a bridge to subjectivity.

Neurological and informatic models of subjectivity will no doubt have their uses and values, as did mechanistic models of the world before them...

[elte]

We still need to figure out how to determine what a particle will do based on very numerous influences acting on it, influences that fully follow physical laws, yet that we know too little about still.

[Yazata]

EXCERPT: [...] Yet, as some philosophers of the early 20th century began to point out, physicalism contains a logical flaw. If consciousness is a secondary byproduct of physical laws, and if those laws are causally closed – meaning that everything in the world is explained by them (as physicalists claim) – then consciousness becomes truly irrelevant.

As long as we are talking about 'logical flaws', how does the irrelevance of 'consciousness' (whatever that word means) follow from its hypothetical reducibility to physics?

Physicalism further allows us to imagine a world without consciousness, a ‘zombie world’ that looks exactly like our own, peopled with beings who act exactly like us but aren’t conscious.

It does? How could a 'zombie' be exactly like us, if the zombie had no emotions, no memory and no ability to be sensitive to and able to react to its own inner states? If somebody was trying to create a human-like robot, it would obviously have to have those kind of functions. There's an implicit and unstated assumption about what 'consciousness' has to be lurking in there.

Such zombies have no feelings, emotions or subjective experience; they live lives without qualia.

What are 'qualia'? If they are information, then there seems to be no incompatibility with physicalism. But if we initially assume that they are metaphysical beings in their own right, kinds of ontological 'stuff' as David Chalmers seems to want to conceive of them, and if they aren't physical stuff, then dualism is already being baked into the premises of the argument and the whole 'qualia' argument for metaphysical dualism becomes circular.

But perhaps most surprisingly, just when the ‘stream of consciousness’ was entering our lexicon, physicists began to realise that consciousness might after all be critical to their own descriptions of the world. With the advent of quantum mechanics they found that, in order to make sense of what their theories were saying about the subatomic world, they had to posit that the scientist-observer was actively involved in constructing reality. [...]

The idea that 'consciousness' "collapses the wave function" is one very idealistic spin on the Copenhagen interpretation of quantum mechanics (which isn't the only interpretation by any means). It's true that some of the early quantum physicists did speculate about quantum idealism, but most of them were Germans or others educated in the German philosophical tradition, which at the time was dominated by the legacy of Kant. (It was soon after German unification, a time of great German nationalism, and since Kant was perceived as the greatest German philosopher, he must be the greatest philosopher of all time.) Garbage in, garbage out.

Andrew Truscott, the Australian scientist who spearheaded the helium work, noted in Physics Today that ‘99.999 per cent of physicists would say that the measurement… brings the observable into reality’. In other words, human subjectivity is drawing forth the world.

Again, an idealistic non-sequitur.

The physical world certainly seems to exist and virtually none of it has been subjected to 'measurements'. I think that what this guy might be reaching for is the idea of interactions. I do think that most quantum physicists think that various physical variables of microcosmic particles can remain undefined until the particles are forced to interact with other matter, whether that's a scientific measuring apparatus or not.

Not all physicists are willing to go down this path, however, and there is indeed now a growing backlash against subjectivity.

I don't think that the 'subjectivity' of quantum idealism has ever been the majority view among physicists.

That has brought into being the so-called ‘many worlds interpretation’ (MWI) of quantum theory.

Wasn't the many-worlds interpretation advanced to eliminate the Copenhagen interpretation's 'collapse of the wave function'?

This fissiparous seething is one of the few ways to interpret quantum behaviour without awarding consciousness a central role

The 'collapse of the wave function' doesn't require that it's some metaphysically separate category of 'mind' that's somehow orchestrating the collapse. Perhaps physical causation on the microscale is inherently probabilistic and God really does "play dice". My impression is that most working physicists think of it in that way.

Some physicists want to be rid of the problem of consciousness altogether, while others are attempting to treat it as a core material phenomenon. Max Tegmark, a theoretical physicist at the Massachusetts Institute of Technology, for example, hopes that consciousness will turn out to be another state of matter, like a solid, liquid or gas, and he’s calling for physicists to begin exploring the ‘physical correlates of consciousness’. What, he asks, are the physical conditions that pertain when consciousness is present?

Tegmark is one of those physicists-turned-metaphysicians, famous for his rather Pythagorean insistence that mathematics is the ultimate 'stuff' of reality.

My own suspicion is that he's off on a fool's errand with his 'physical correlates of consciousness' project. Nothing is likely to come of it. Physics isn't the right science to investigate 'consciousness' any more than it's the right science to understand life. Physicists can investigate particle physics all they like and they aren't going to find that life is another state of matter in the same way that solids, liquids and gasses are.

In order to understand life, one has to ascend up the pyramid of reducibility a bit, through chemistry (which is reducible in part to physics) and biology (which is reducible in part to chemistry). As the elementary entities of physics come together in chemical compounds, we see new chemical phenomena making their appearance. And as chemical molecules come together in biological organisms, new biological phenomena make their appearance.

My expectation is that psychology rides atop biology in much the same way that biology rides atop chemistry. As biological nervous systems come together to form more and more elaborate data-processing systems, new behavioral phenomena appear. In other words, the sciences that are best positioned to attack the problem of consciousness are computer science, cognitive science, robotics and artificial intelligence. These aren't questions that physics is going to answer.

And philosophy has its vital role to play too. In my opinion, 'consciousness' needs to be reconceptualized as something behavioral, as actions that organisms perform, rather than as some kind of occult substance in the manner of the immortal soul. So any progress in understanding consciousness in physicalistic terms is probably going to be dependent on a philosophical reconceptualization of the subject, much as the scientific revolution in physics succeeded in reconceptualizing physical phenomena in terms different than those of medieval Aristotelianism.

[C C]

[...] Wasn't the many-worlds interpretation advanced to eliminate the Copenhagen interpretation's 'collapse of the wave function'?

It's taken to be a realist view -- the multiplicity of a particle's states are each treated as actual rather than as an abstract generalization that "collapses" into a specific one upon being disturbed. Most if not all of the realist interpretations are considered strange in their own right. So the Copenhagen interpretation has hung around in dominance over the decades, though it may have dipped below the 50% mark recently. Which doesn't necessarily mean any of the other views has yet acquired larger support as a result. The CI itself was something culled and developed by others from Bohr's lectures, rather than his own direct product. In the context of the positivist era which CI was spawned in, the original "prototype" papers and talks were probably intended by Bohr to be a way of avoiding any metaphysical or ontological conclusions about what the mathematical descriptions meant, rather than later becoming one itself.

And philosophy has its vital role to play too. In my opinion, 'consciousness' needs to be reconceptualized as something behavioral, as actions that organisms perform, rather than as some kind of occult substance in the manner of the immortal soul.

Consciousness treated as just outward behavior (minus introspective experiences or manifestations) has been tried in the past, with the result of cognitive science (etc) eventually developing because of the former's limitations. It's unclear how the personal thoughts of scientists not spoken aloud or written down could be known to them (the alternative form of evidence involved), as well as dreams and hallucinations that were not publicly disclosed.

Why or how the extrospective environment of body behaviors would be "showing itself" to scientists as visual and aural phenomena, while the introspective content was not is also puzzling. Perhaps both varieties of experience (inner / outer) were sometimes dismissed as occurring, so that the scientist was then a kind of successful blindsight, deaf-hearing, and so-forth kind of zombie.