Book review: Giulio Tononi’s Phi: A Voyage from the Brain to the Soul | Minds and Brains: Here is how integrated information is defined:
Integrated information measures how much can be distinguished by the whole above and beyond its parts, and [phi] is its symbol. A complex is where [phi] reaches its maximum, and therein lives one consciousness- a single entity of experience.
And with that Tononi hopes the “hard” problem of consciousness is solved. However, the intellectual weight of Phi rests on a thought experiment involving a photodiode. A photodiode discriminates between light and no light. But does the photodiode see the light? Does it experience the light? Most people would think no. But the photodiode does integrate information (1 bit to be precise) and therefore, according to the theory of integrated information, has some experience, however dim. The theory of integrated information is therefore a modern form of panpsychism based on the informational axiom of “it from bit”.