The question of what constitutes consciousness arouses quite a bit of controversy, around what is known as ‘the hard problem of consciousness’. Here is a description of what that is.
The hard problem of consciousness is the problem of explaining why any physical state is conscious rather than nonconscious. It is the problem of explaining why there is “something it is like” for a subject in conscious experience, why conscious mental states “light up” and directly appear to the subject. The usual methods of science involve explanation of functional, dynamical, and structural properties—explanation of what a thing does, how it changes over time, and how it is put together. But even after we have explained the functional, dynamical, and structural properties of the conscious mind, we can still meaningfully ask the question, Why is it conscious? This suggests that an explanation of consciousness will have to go beyond the usual methods of science. Consciousness therefore presents a hard problem for science, or perhaps it marks the limits of what science can explain. Explaining why consciousness occurs at all can be contrasted with so-called “easy problems” of consciousness: the problems of explaining the function, dynamics, and structure of consciousness. These features can be explained using the usual methods of science. But that leaves the question of why there is something it is like for the subject when these functions, dynamics, and structures are present. This is the hard problem.
In more detail, the challenge arises because it does not seem that the qualitative and subjective aspects of conscious experience—how consciousness “feels” and the fact that it is directly “for me”—fit into a physicalist ontology, one consisting of just the basic elements of physics plus structural, dynamical, and functional combinations of those basic elements. It appears that even a complete specification of a creature in physical terms leaves unanswered the question of whether or not the creature is conscious. And it seems that we can easily conceive of creatures just like us physically and functionally that nonetheless lack consciousness. This indicates that a physical explanation of consciousness is fundamentally incomplete: it leaves out what it is like to be the subject, for the subject. There seems to be an unbridgeable explanatory gap between the physical world and consciousness. All these factors make the hard problem hard.
I must admit I that while I have read many accounts of the hard problem, I still do not get what the mystery is. As a dyed-in-the-wool materialist, I believe that our consciousness and actions are the product of the physical workings of our body, particularly the brain, and that there is nothing immaterial involved and I am baffled as to why it is seen as beyond the limits of scientific explanation. The so-called ‘easy problems’ of consciousness that deal with the ‘function, dynamics, and structure’ of consciousness seem to me to be all that there is. There is no unbridgeable gap. If you have “a complete specification of the creature in physical terms”, then you have solved the problem. I am not sure what the statement that “It appears that even a complete specification of a creature in physical terms leaves unanswered the question of whether or not the creature is conscious” even means. The people who say that seem to be simply asserting that there must be more. But why should there be?
The latest controversy over consciousness is reported on in the journal Nature.
A letter, signed by 124 scholars and posted online last week, has caused an uproar in the consciousness-research community. It argues that a prominent theory describing what makes someone or something conscious — called the integrated information theory (IIT) — should be labelled as pseudoscience. Since its publication on 15 September in the preprint repository PsyArXiv, the letter has resulted in some researchers arguing over the label and others worrying that it will increase polarization in a field that has grappled with issues of credibility in the past.
“I think it’s inflammatory to describe IIT as pseudoscience,” says neuroscientist Anil Seth, director of the Centre for Consciousness Science at the University of Sussex near Brighton, UK, adding that he disagrees with the label. “IIT is a theory, of course, and therefore may be empirically wrong,” says Christof Koch, a meritorious investigator at the Allen Institute for Brain Science in Seattle, Washington, and a proponent of the theory. But he says that it makes its assumptions — for example, that consciousness has a physical basis and can be mathematically measured — very clear.
But why label IIT as pseudoscience? Although the letter doesn’t clearly define pseudoscience, Lau notes that a “commonsensical definition” would be “something that is not very scientifically supported, that masquerades as if it is already very scientifically established”. In this sense, he thinks that IIT fits the bill.
So what is IIT?
There are dozens of theories that seek to understand consciousness — everything that a human or non-human experiences, including what they feel, see and hear — as well as its underlying neural foundations. IIT has often been described as one of the central theories, alongside others such as global neuronal workspace theory (GNW), higher-order thought theory and recurrent processing theory. It proposes that consciousness emerges from the way information is processed within a ‘system’ (for instance, networks of neurons or computer circuits), and that systems that are more interconnected, or integrated, have higher levels of consciousness.
One of the criticisms made of IIT that its critics claim make it a pseudoscience is that its core assumptions are purportedly not testable, a charge that its supporters reject.
Seth, who is not a proponent of IIT, although he has worked on related ideas in the past, disagrees. “The core claims are harder to test than other theories because it’s a more ambitious theory,” he says. But there are some predictions stemming from the theory, about neural activity associated with consciousness, for instance, that can be tested, he adds. A 2022 review found 101 empirical studies involving IIT.
Liad Mudrik, a neuroscientist at Tel Aviv University in Israel who co-led the adversarial study of IIT versus GNW, also defends IIT’s testability at the neural level. “Not only did we test it, we managed to falsify one of its predictions,” she says. “I think many people in the field don’t like IIT, and this is completely fine. Yet it is not clear to me what is the basis for claiming that it is not one of the leading theories.”
The same criticism about a lack of meaningful empirical tests could be made about other theories of consciousness, says Erik Hoel, a neuroscientist and writer based in Cape Cod, Massachusetts. Hoel is also a former student of Giulio Tononi, a neuroscientist at the University of Wisconsin–Madison who is a proponent of IIT. “Everyone who works in the field has to acknowledge that we don’t have perfect brain scans,” Hoel says. “And yet, somehow, IIT is singled out in the letter as this being a problem that’s unique to it.”
Consciousness has shifted from being a deep mystery that we did not how to empirically address and that only philosophers and religious people debated, to becoming an empirical question, to becoming a puzzle about which we can now pose focused questions and do experiments. The study of the brain’s workings have become possible with the advent of MRI machines and the like. If science history is any guide, once that transition from mystery to puzzle occurs, it is only a matter of time before we achieve a fairly good consensus on understanding it.
So while getting an understanding of the nature of consciousness is not easy, it is going to get clarified as our technological abilities improve.
You can read the letter that critiques IIT here.