Back in 1998, premier neuroscientist Christof Koch had wagered philosopher of mind David Chalmers a case of fine wine that within the next twenty-five years, a specific “signature of consciousness” would be found in the brain. In 2018, Swedish journalist Per Snaprud reminded the world of that fact at New Scientist. With five years to run, a countdown of sorts began. Snaprud’s article was titled “Consciousness: How we’re solving a mystery bigger than our minds,” telling readers that “we’re uncovering clues.”

The five years are up and who won? Mariana Lenharo reports at Nature, “Both scientists agreed publicly on 23 June, at the annual meeting of the Association for the Scientific Study of Consciousness (ASSC) in New York City, that it is still an ongoing quest — and declared Chalmers the winner.” So there is no known signature of human consciousness in the brain. We all sense that we are conscious but that sense is not located in any one place or current.

The wagerers were well matched. Koch (pictured), from the Allen Institute for Brain Science in Seattle, is the leading proponent of Integrated Information Theory (IIT), which he admits is panpsychist (all life and perhaps even non-life is conscious to some extent).

Chalmers, co-director of the Center for Mind, Brain and Consciousness at New York University, originated the term “Hard Problem of Consciousness.” He told Robert Lawrence Kuhn at Closer to Truth that he accepts dualism (the human mind is immaterial) though he does not believe in an immortal soul:

There’s this problem with consciousness: It just leaves a gap. Every physical theory ever devised leaves a gap to consciousness. So I banged my head against the wall for years trying to come up with a physically based theory of consciousness. Every week I had a different physical theory of consciousness. None of them worked and eventually I came to see this is for systematic reasons. There are reasons why no purely physical theory will ever give you consciousness. It’ll always be an objective theory of objective functions. None of that ever gives you subjective experience. (:55)

Perhaps it’s significant that neither contestant is a physicalist like King’s College philosopher David Papineau, who tells us “If only we could stop ourselves seeing things through dualist spectacles, we’d no longer feel that there is anything puzzling about consciousness.” And, as it happens, the dualist won the bet.

How did Chalmers win? A contest between two theories of consciousness, announced by Templeton World Charities in 2019, enabled the bet to focus on specifics: Koch’s Integrated Information Theory was pitted against Global Network Workspace Theory. GNWT relies on information theory to image consciousness via observations of the brain at work.

From Nature, we learn,

Integrated information theory (IIT) and global network workspace theory (GNWT). IIT proposes that consciousness is a ‘structure’ in the brain formed by a specific type of neuronal connectivity that is active for as long as a certain experience, such as looking at an image, is occurring. This structure is thought to be found in the posterior cortex, at the back of the brain. On the other hand, GNWT suggests that consciousness arises when information is broadcast to areas of the brain through an interconnected network. The transmission, according to the theory, happens at the beginning and end of an experience and involves the prefrontal cortex, at the front of the brain. – Mariana Lenharo, Decades-long bet on consciousness ends — and it’s philosopher 1, neuroscientist 0, Nature, June 24, 2023

The six independent laboratories that tested the hypotheses came up with results which did not match either theory perfectly. But in any event, the “signature of consciousness” was never captured. Chalmers told Nature nonetheless that “There’s been a lot of progress in the field” and that “over the years, it’s gradually been transmuting into, if not a ‘scientific’ mystery, at least one that we can get a partial grip on scientifically.” And Koch bought a case of fine Portuguese wine in New York City, the day before the results were announced…

Interestingly, a 2022 study of consciousness theories out of Tel Aviv University analyzed four leading theories and found that “Each of these theories offers convincing experiments to support them, so the field is polarized, with no agreed-upon neuroscientific account of consciousness.”

And there it sits.

Neurosurgeon Michael Egnor points out that we can’t even define consciousness, which surely complicates the search for its signature. For example, in a recent review of Kenneth Miller’s book, The Human Instinct, (Simon and Schuster, 2018) he notes, “Miller doesn’t define consciousness, because consciousness is a notoriously slippery concept that is never coherently defined in neuroscience or in philosophy.” He adds,

“Consciousness” is a clear example of what Wittgenstein called a language game. A language game is the rule-governed meaning that words acquire by their use in ordinary life. Sometimes we use consciousness to mean arousal, sometimes we use it to mean perceptual knowledge and at other times we use it to mean abstract comprehension or carefulness or realization. Whatever its value in ordinary language, “consciousness” has no place in the discussion of neuroscience or philosophy. This is not because we aren’t aware or we aren’t capable of perception or understanding. The problem is that the term consciousness is too vague to be useful in neuroscience or in the philosophy of mind. The meaning of consciousness is so broad – its language game is so convoluted – as to preclude genuine insight. – Michael Egnor, “Kenneth Miller on consciousness and evolution,” Mind Matters News, March 8, 2023

But a language game may have its uses. One of them may be to circumvent a growing realization. In this case, the realization is that Chalmers and other dualists are right: There is an immaterial aspect to human nature that is not addressed by, say, searches for a consciousness spot or signature in the brain. If that sounds uncomfortable, well, there is always the language game.