[easyazon-image align=”left” asin=”030790721X” locale=”us” height=”250″ src=”http://ecx.images-amazon.com/images/I/4173njDrKKL.jpg” width=”170″]Will neuroscience ever explain consciousness? With the surfeit of philosophic trench warfare over the past 20 years, one has good reason to feel skeptical. Whether explained away by the deterministic rigor of reductive materialism or obscured by the epistemological fog of mysterianism, a serious analysis of the conceptual landscape has left the study of consciousness stranded between the Scylla and Charybdis of hard-line materialism and amorphous idealism. Attempts at a middle-way couldn’t make-up in conceptual parsimony what they lost in empirical rigor.
It’s clear that University of Wisconsin-Madison neuroscientist Giulio Tononi was paying close attention to these skirmishes when he generated his own theory of consciousness, informed as it is by both conceptual concerns and empirical neuroscience. Tononi’s Integrated [easyazon-link asin=”0486240614″ locale=”us”] Information Theory [/easyazon-link](IIT) is one of the first serious attempts at a comprehensive, mathematically rigorous, and biologically informed theory which strives to tackle this hardest of problems. Amazingly, it may just be true. Over a string of remarkable scientific papers, Tononi has attempted to systematize an explanatory paradigm for consciousness based on information theory. Before accessible only to specialists in [easyazon-link asin=”0137155166″ locale=”us”] neuroscience [/easyazon-link] or philosophy, Tononi has now turned his theory into a popular science book like no other. The title comes from the symbol he has come to associate with consciousness: Phi. Here is an exploration of mind worthy of its subject, as aesthetic in execution as it is scientific in purpose.
Phi tells the imaginary story of an aged Galileo Galilei, who, dreaming of the paradox of consciousness is taken on a scientific journey by three ghostly guides: Francis Crick, the discoverer of DNA who spent his latter years tirelessly seeking a neuroscientific understanding of consciousness,[easyazon-link asin=”0470229055″ locale=”us”] Alan Turing [/easyazon-link], the brilliant founder of modern computation, and finally Charles Darwin himself. The intimation here is clearly Dante, but Dickens’ A Christmas Carol is a more accurate template for Galileo’s adventure. These guides take the old scientist into the depths of our biological and theoretical understanding of the human brain. The journey traverses a world which the Italian Tononi must know in his bones: a European landscape populated by enlightenment philosophers, 16th Century papal physicians, Parisians artists and Renaissance cartographers. Phi feels like it was written in the shadow of Pisa’s famed leaning tower, surrounded by Titian frescoes and stacks of yellowing manuscripts.
At the IIT’s heart is a thought-experiment involving a photo-diode and information theory; in a nutshell, consciousness is defined by the discriminations the brain can make as compared to the discriminations the diode can make. At the center of the IIT is the idea that consciousness is a single system’s reduction of uncertainty as a whole, selecting one out of many possible states that it could be in. And since the discrimination is of the entire system, it is always defined as the information that the whole system generates over and above its parts. The theoretical triumph of Tononi’s scheme is the way that it quantizes and makes literal the hackneyed observation that we are “more than the sum of our parts.” If correct, this overused aphorism is literally why we’re conscious at all.
[easyazon-image align=”left” asin=”1578591376″ locale=”us” height=”160″ src=”http://ecx.images-amazon.com/images/I/514XlbJ2QGL._SL160_.jpg” width=”118″]But let’s dig deeper: Just what is integrated information? The IIT is a mighty scaffolding upon which many [easyazon-link asin=”0061358134″ locale=”us”] metaphors [/easyazon-link] can be hung, but here’s one way to make the concepts a little clearer: Imagine the neo-cortex (or any causal network, actually) is a rolodex with a discrete number of cards, each card representing an irreducible state that the system can be in. (The number of cards is determined by the number of nodes and variety of connections in the system’s network.) The IIT claims that a particular causal organization allows a network to reduce uncertainty about it’s own state by essentially “asking” a string of binary yes-no questions. (“Is there a shape in front of me?” “Is it a square?” “A circle?” “Is it blue?” “Red?” Etc.) With each “answer” the system throws away all the cards that do not apply, reducing uncertainty about what state it actually IS in; it eliminates alternatives. So, any system wired in such a way as to reduce uncertainty about itself as a whole can be said to generate integrated information. (In fact, this ability to generate integrated information is what makes something a single system at all and not just a collection of smaller systems; a conscious state is always one thing.) After it asks all the questions that its causal mechanisms allow, the neo-cortex must select one card from the few remaining in the rolodex. The system “chooses,” based on what it knows it is not, saying, in essence: “I think the world is like THAT.” Compared to the photo-diode, which can only select from a rolodex with two cards, 0 and 1, the human neo-cortex generates vastly more bits of information. If one accepts, as a basic axiom, that integrated information is the necessary and sufficient condition for consciousness, the human brain looks like the perfect machine to generate vast quantities of it. Our rolodex has many cards indeed.
But more than just an exposition of a scientific theory, Phi is also beautiful. The book itself is something of a consciousness raiser, filled with glorious illustrations, paintings, and portraits. With the well-chosen art complimenting Tononi’s rich, sumptuous language, one experiences many modalities of their own [easyazon-link asin=”0195179595″ locale=”us”] consciousness [/easyazon-link] while reading Phi, a triumphant merger of content and style.
Always aiming for clarity and beauty, Tononi doesn’t lard us over with citations. Nor does he argue directly against the many materialist accounts of consciousness popular today. With immense style and skill, Tononi takes us back to the beginning, as if we, like Galileo, knew nothing about the brain. Phi explores anew what consciousness IS, from the ground up. I believe, in time, Tononi’s name will be equal to Einstein, Newton and, yes, Galileo, in the pantheon of human thought. The IIT is the beginning of a fundamental revolution in science and in human consciousness itself. Phi is nothing short of a masterpiece.