[NOTE – this is re-post from the original incarnation of this blog.]
The existence of non-epiphenomenal consciousness and free will are two different, but related issues. Both are disputed by those of a physicalist persuasion, and both find themselves lacking any place within our current scientific understanding of the world. Indeed, they not only have no place, but also run contrary to a key precept of modern science: that there is no such thing as an uncaused cause.
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In the classical Newtonian picture of physics, the processes that lead to a particular brain state are governed by deterministic laws of nature. If in principle we could perfectly describe a starting brain state, then by extrapolation using those laws, we can predict with certainty a subsequent brain state. Quantum mechanics overthrows this view, revealing that fundamentally, all processes are probabilistic in nature. Instead of predicting with certainty, instead we only have a probability that one result will win out over another (even if in macroscopic systems there are so many quantum elements that the law of averages means the probability is very high indeed). This introduces a random element to the possible evolution of systems over time, but doesn’t necessarily help with defending free will. A random result is not necessarily a free one.
This fundamentally random, but practicably deterministic state of affairs is what we observe in every area of nature we’ve ever cared to study. Physical processes alone are sufficient to explain the evolution of systems in time. So what role could mental processes have if they exist at all? And even if there is a role, by what conceivable mechanism could a mental process affect a physical process? This is the problem of defending non-epiphenomenal consciousness.
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Beyond questions of the efficacy of conscious systems looms the even more unlikely notion of traditional incompatibilist free will; a concept seemingly so contrary to what we know about nature that most philosophers and scientists appear to have abandoned it altogether. And it’s not difficult to see why. The suggestion appears to be that not only does the mind play a role in the evolution of brain states, but that it can also derail the chain of cause and effect by somehow tipping the probabilities in favour of what would otherwise be a vanishingly unlikely alternative options.
Given those facts, how can defenders of causally efficacious mind and free will construct a believable argument for their existence?
To be taken seriously, both non-epiphenomenal consciousness and free will are desperately in need of a viable mechanism. Without it, both are rightly open to attack as being only explainable by supernatural forces. And to be viable, I would argue that any proposed mechanism would have to both conform to our current best-fit scientific theories and be robust enough to be considered mainstream.
Some may claim that such questions are outside the scope of science altogether, being that evidence for their existence is purely subjective and therefore unverifiable by the scientific method. With most such phenomena I would agree. For instance, believers in gods may try to claim that their experience of the divine counts as evidence, while others use subjective experience to underpin all sorts of dubious pseudoscience and quackery. So right away, I should make it clear that I consider non-epiphenomenal consciousness and free will worthy of explanation for one reason alone: they are – at first blush at least – subjectively universal phenomena. Even the most ardent physicalist must admit that without further reflection, we appear to have both. That of course is not proof – appearance often misrepresents reality – but it is I think, at least reason to investigate as best we can with an open mind.
An axiom attributed to ancient Greek philosopher Parmenides and later made famous in the modern Western world by William Shakespeare in King Lear says that “nothing comes from nothing“. The antithesis of this idea is the idea of creation ex nihilo, or “out of nothing”. The gods of many religious traditions are supposed to have pulled off such a trick at the beginning of the universe, and – unfortunately for defenders of non-epiphenomenal consciousness and free will – it’s a trick that agents seemingly also need to perform every time they exercise free will. They have to introduce or create some new event that is neither random nor wholly dependent on prior physical causes.
However, modern science has put that axiom under pressure, leading us to question whether it really is such a self-evident truth. It’s not that science has shown that matter or energy can be created ex nihilo (indeed, that would violate another key idea in physics; that of the conservation of energy enshrined in the first law of thermodynamics) but rather that modern science now suggests that the very concept of nothingness may be meaningless.
The quantum fields that make up the universe, such as the electromagnetic field and the Higgs field all have a ground state – a lowest possible energy configuration – slightly above zero, making them subject to quantum fluctuations. This is the case even in a complete vacuum, hence the name vacuum energy, although the property as applied to each field is known as zero point energy. But a vacuum is the only physical (i.e. non-abstract) definition of nothingness that makes sense within the bounds of the universe, so physically-speaking there is no such thing as nothing.
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Because excitations in quantum fields are one and the same as point particles in the standard model, this vacuum energy manifests as the creation of virtual particle/antiparticle pairs that briefly pop into existence and immediately annihilate each other. This fact applies not only to the vacuum or to space, but to every part of the universe. This vacuum energy can be thought of like the fizzing surface of a liquid, with each bubble being that brief pair of particles that burst into existence only to almost immediately pop out of it again, although it is important to note that this energy is usually both unmeasurable and unavailable to macroscopic processes – it is not some mystical energy field one can use to justify belief in dubious phenomena!
In technical terms, these particles exist for a time shorter than the Planck time, which means that due to the time-energy relationship in Heisenberg’s uncertainty principle, they remain unmeasurable and insubstantiated in the physical world. Hence the label virtual particles as opposed to actual particles we can measure.
However, just because they are virtual, one shouldn’t imagine that they play no role in the physical world. Not only have experiments shown them to be most-likely responsible for proven phenomena such as spontaneous emission, the Casimir effect, and the Lamb shift, but they are also generally thought to mediate the interaction of real particles in quantum field theory. For example, the exchange of virtual photons underlying the interaction of electrons in electromagnetism.
The only way these virtual particles can achieve actualisation and gain any kind of permanence is to draw on the energy in the surrounding environment, whilst avoiding mutual annihilation.
One situation in which this is thought to be possible is in the extreme environment of a black hole. These gravitational sink-holes bend space so severely that even the fastest moving objects in the universe – photons of light – do not have sufficient escape velocity to avoid falling into their clutches. This results in the formation of a boundary, or event horizon, from which no matter or energy can escape.
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Now consider a particle/antiparticle pair that forms at the event horizon of a black hole. In simple terms, if one of the pair forms inside the event horizon and the other on the outside, then they will not be able to interact and annihilate, and drawing on the gravitational energy of the black hole, they actualise. So both an observer on the interior of the horizon, and one on the outside witness the emission of particles as radiation. This is known as Hawking radiation after physicist Stephen Hawking who first conjectured its existence.
As previously stated, this isn’t really ex nihilo creation of matter or energy, because the creation process is driven by the intrinsic zero point energy of quantum fields, plus the energy of the surrounding system. Thus the principle of conservation of energy also means that the system involved must lose some of its own energy, or in the case of black holes the equivalent mass. In this way black holes starved of infalling matter are though to slowly but surely evaporate.
Another consequence is that the more mass or energy a system has, the greater the mass or energy of the particles that can be emitted. So whilst there are also hypothesized micro black holes, produced primordially in the early universe and perhaps still existing today, the Hawking radiation they would emit would consist only of low mass particles like electron/positron pairs or photons, which are massless and their own antiparticles. (Note that even in normal black holes, Hawking radiation is dominated by photons).
But black holes are not the only situation where this type of particle creation can occur. In theory, any energetic phenomena that forms an event horizon can perform the same trick.
One such phenomenon is known as the Unruh effect, and is a logical consequence of Einstein’s realisation that the gravitational force is equivalent to acceleration. Here an accelerating system gains kinetic energy from the gravitational field which then – from the point of view of an observer in the same relativistic reference frame as the accelerating system – results in a radiation bath in that internal frame, as particle/antiparticle pairs actualise before annihilating. And just like the black hole case, because an accelerating system creates an event horizon (the reason for which is beyond the scope of this piece), the equivalent of Hawking radiation is also witnessed by observers outside that horizon.
In both examples, we have the formation of an event horizon creating a one-way barrier between an enclosed volume of space (the interior of the black hole and the relativistic reference frame) and the rest of the universe.
So, returning to consciousness, we have – superficially at least – an interesting parallel. In both, the external environment can influence the enclosed internal worlds via the flow of information into them, but from within those enclosed internal worlds one is only able to observe the external universe rather than interact directly with it. However, via a phenomenon such as Hawking radiation, that internal world is able to exert a physical influence back on its environment. By analogy, these phenomena correspond to a mechanism for non-epiphenomenal consciousness.
Now, I’m certainly not suggesting that consciousness resides in microscopic black holes – I’ll leave that to Romulan starships! Nor am I saying that the Unruh effect is responsible. I simply don’t have enough knowledge of physics or mathematics to surmise or calculate how small objects at short distances may or may not produce the acceleration necessary or an event horizon local enough. And I strongly doubt there is anything in mainstream neuroscience to offer as a framework for such effects in the brain.
I’m only suggesting that such seemingly ex nihilo creation would not-so-long-ago have been thought impossible without supernatural intervention in the world, but that zero point energy opens-up the possibility of a variety of effects that might – at least conceivably – be exploited by evolved systems.
Under those speculative lights, the mere possibility of horizon-enduced particle creation in connection to consciousness and the brain would provide a high-level explanatory mechanism for non-epiphenomenal consciousness. And if such creation could be directed and (perhaps chaotically) amplified, one might see how such internally-produced nudges might pave the way for free will.
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At such low energies, any such creation would have to be in the form massless particles like photons, and whilst this might bring its own problems in accounting for how they might deliver the needed nudges to existing processes, on the other hand, such effects should in principle be measurable and therefore testable. It should be noted that there is already some speculation about the role of photons in the brain, though stressed that this is not mainstream.
Of course, even if there is something in my speculation, many issues might remain unresolved, such as the hard problem of consciousness and how the mental domain might manage to muster and direct its will; not to mention under what ontology and laws consciousness itself might operate internally.
Also, there is danger here in stepping too far with speculative ideas. Scientists and rational thinkers are wary of any non-physicalist speculation on consciousness, I suspect because to do so opens the door to all sorts of religious and pseudoscientific nonsense that are neither objectively testable or even subjectively universal. So it’s important to not speculate more than a single step beyond our current knowledge, and to do so without any preconceptions of where one is heading.
But with that caution in mind, I still think it’s fair to say that this class of phenomena in physics at least shines a light into the domains in which we should search for clues. And even if such speculation proves fruitless, it serves to illustrate how science continually surprises us with unexpected phenomena. So while admitting that the existence of non-epiphenomenal consciousness and free will remain improbable, we should not lose hope. Closing the door on what are our most universal and all-encompassing experiences of reality – that our minds interact with and affect the physical world – is premature.