Giulio Tononi, a University of Wisconsin psychiatrist and neuroscientist, invented the Integrated Information Theory of consciousness. Online in Scientific American last Friday, he published an excerpt of a new book, titled “PHI: A Voyage from the Brain to the Soul,” in which he expounds his ideas.
“Consciousness lives where information is integrated by a single entity above and beyond its parts,” he writes in the subheading of the published chapter. (...)
The core of Intergrated Information Theory is the identification Tononi makes of consciousness with “the information generated by the whole above and beyond its parts,” which he calls “integrated information.” Using a measure of information derived from information theory, he assigns this bonus quantity of information the symbol Ф.
As an example, Tononi imagines a row of men. If each is whispered the word of a single sentence, each man may think of that word, but “nowhere will there be a consciousness of the whole sentence,” Tononi writes. (...)
In the case of the men in a row, Ф is the quantity of information that corresponds to the meaning of the sentence, which does not emerge until each man speaks his word. (...)
When information is exchanged between objects (i.e., when photons pass between them), the wavefunctions of those objects become entangled, and to some extent merge together (overlap) as a single wavefunction. Thus, when the men exchange the information of their words, the wavefunctions of their brains entangle and overlap to a degree. Their individual brain wavefunctions come to share a mathematical component — a factor, if you will — and that shared component corresponds to the meaning of the sentence.