Integrated Information Theory
One of several scientific attempts to explain why brains feel like something, and a rare case where rival theories were tested head to head.
Giulio Tononi proposed integrated information theory in 2004. It says consciousness is tied to how much a system's parts act together as one unified whole, a quantity called phi. On this view, what matters is the structure of cause and effect, not what the system is made of.
Rival theories exist, such as global workspace theory. In 2023 a large collaboration reported the first results of an adversarial test designed to pit them against each other. Neither theory came out clearly ahead, and the results drew open criticism, including a public letter by many researchers calling IIT pseudoscience.
That dispute is why this belongs in the Almost credible group: it is real, funded, published research with real data, but nothing is settled and serious scientists disagree about whether it is even testable.
Under IIT, a system does not need to be a brain to have some degree of consciousness, which critics say leads to strange conclusions.
In 2023 a letter signed by more than a hundred researchers argued that IIT should be labeled pseudoscience.
