09 — The Wager

A Case of Wine

a neuroscientist, a philosopher, and twenty-five years to find the place in the brain where experience lives

In June 1998, after a day of lectures at a consciousness conference in Bremen, the neuroscientist Christof Koch and the philosopher David Chalmers went on to a bar and stayed until it was light outside. Koch offered a bet. Within twenty-five years, he said, someone would find a specific signature of consciousness in the brain. Chalmers said no one would. The stake was a case of fine wine.

1998 → 2023 → 2048

The two men stood on either side of a question Chalmers had named in a paper three years earlier. Explaining what the brain does — how it sorts signals, directs attention, produces speech — is hard work, but it is the ordinary kind. Explaining why any of that is felt, why there is something it is like to see red, is a different kind of problem. He called it the hard problem. Koch, who had worked with Francis Crick since the mid-1980s, was looking for the neural correlates of consciousness: the smallest set of brain activity that is enough for a particular experience. That search does not answer the hard problem. It goes around it, and for that reason researchers of almost any philosophical view can take part in it.

Twenty years later, neither man could remember exactly what they had agreed. The journalist Per Snaprud had interviewed Chalmers in Bremen the day after the bet, and he found the cassette in a box in his study. On the tape, Chalmers gives the terms: “a small set of neurons characterised by a small list of intrinsic properties,” fewer than ten of them, and clear within twenty-five years.

The bet came due as a large experiment was being run. The Cogitate Consortium was designed as an adversarial collaboration. The proponents of two rival theories, integrated information theory and global neuronal workspace theory, agreed in advance and in public on what each theory predicted and what result would count against it. Labs that were not committed to either theory then ran the tests, using fMRI, MEG and electrodes placed inside the skull. The first results were presented at the meeting of the Association for the Scientific Study of Consciousness in New York on 23 June 2023. Neither theory came out clean. When the full study of 256 people was published, it supported parts of both and contradicted central claims of each. Koch conceded and paid. He then offered a second bet, another twenty-five years, due in 2048, and Chalmers took it. Chalmers said he hoped to lose and expected to win.

The bet did not show that consciousness is beyond science. It showed only that one specific, checkable prediction failed within the time allowed. The experiment did not settle it either. The argument over whether one of the two theories can be tested at all grew sharp enough that in 2023 more than a hundred researchers signed a letter calling it pseudoscience, and in 2025 its defenders answered in print. What the wager does record is a rare thing in this subject: a question about experience stated precisely enough to lose. Both men who made the bet are listed among the authors of the paper that came out of it.