So Galileo felt, for the first time in a long time, that he must write what he had learned. And this is what he wrote:
Integrated information measures how much can be distinguished by the whole above and beyond its parts, and Φ is its symbol. A complex is where Φ reaches its maximum, and therein lives one consciousness— a single entity of experience.
Notes “The whole is more than the sum of its parts” is an expression that comes from Aristotle’s Metaphysics, which Galileo knew well. William James thought that integration was a key to consciousness and fought hard to understand it, as revealed by some excerpts from his Principles of Psychology integrated into this chapter. Unfortunately he never succeeded and eventually gave up amid doubts and denial, writing an essay with the revealing title “Does Consciousness Exist?” James’s photograph is from the Houghton Library, Harvard University. The all-sky night photograph of the Northern Galactic Hemisphere (on the left) was taken by Tunç Tezel at the Canary Islands; the Southern Galactic hemisphere (on the right) was taken by Stéphane Guisard in the Acatama Desert. The picture obtained by joining the horizons of the two all- sky images was the Astronomy Picture of the Day on July 30, 2011 (A Tale of Two Hemispheres). If integrated information, measured by Φ (the Greek letter phi), is indeed the weighty concept at the heart of consciousness that it is claimed to be, this chapter introduces it in a rather light- weighted manner. Perhaps the author was trying to avoid equations at all costs, but the result is far from satisfactory. Versions of Φ dressed in equations, but in the end just as unsatisfactory, are found in Tononi and Sporns, BMC Neuroscience (2003); Tononi, BMC Neuroscience (2004); Biological Bulletin (2008); Balduzzi and Tononi, PLoS Computational Biology (2008); Tononi, Archives italiennes de biologie (2010, 2011). Information was defined as “a difference that makes a difference” by Gregory Bateson, in Steps to an Ecology of Mind (University of Chicago Press, 1972). The Ripe Harvest by Klee is at the Sprengel Museum, Hanover, Germany. The last portrait is by Arcimboldo (disliked by Galileo and modified in bad taste, if not bad faith) and is known as Adam (Eve’s counterpart, private collection).