Putting Ourselves Back in the Equation

From The Wall Street Journal:

Popular science often feels like a kind of voyeurism. Those who can’t manage the real thing are given a thrilling glimpse of its intrigue and excitement but kept at a distance. So a book that tackles the mind-boggling triad of physics, consciousness and artificial intelligence might be expected to provide little more than intellectual titillation. The science journalist George Musser even says at its end that “many physicists and neuroscientists are just as perplexed as the rest of us.”

But Mr. Musser knows that the point of popular science is not for the reader to understand everything fully but to get a sense of what’s at stake, what kinds of answers are being offered to difficult questions, and why it all matters. One could not ask more of “Putting Ourselves Back in the Equation”—on all three counts it delivers.

The central puzzle of the book is what the contemporary philosopher William Seager has called a “ticking time bomb”: the intellectual division between the objective and the subjective. Natural science was able to make such great strides after the Middle Ages only because it left the analysis of thoughts and feelings to poets and philosophers, focusing instead on measurable observables. The strategy worked a treat until it hit two brick walls.

The first is the nature of consciousness. Modern neuroscience, at first, stuck to examining the brain events that corresponded to conscious experiences: the “neural correlates of consciousness.” But at a certain point it became clear that such a focus left out a good deal. How is it possible that mushy cells give rise to sensations, emotions and perceptions? The science of mind had to ignore precisely what it was supposed to explain because a purely objective account of consciousness cannot encompass its subjective character.

And then—a second and related problem—physicists discovered that they couldn’t leave conscious minds out of their equations. A central tenet of quantum theory is that observers change what they observe. This is embarrassing. Physics is meant to describe the mind-independent world. But its best description ended up having minds—with their particular points of view—at its center. So for physics to be anything like complete, it has to find a way to kick minds out again or account for what makes them conscious and why they should affect physical matter.

Mr. Musser provides a chatty and informal overview of the many ways in which physicists have been trying to rise to these challenges. He speaks to many of the leading scientists in the field, trying a bit too hard to make them seem like regular folks so that we don’t feel intimidated. A bigger challenge, for the reader, is that he introduces us to so many theories that it’s difficult to judge which should be taken most seriously and which lean toward the cranky. Given that even the most well-evidenced theories in physics sound crazy, our intuitions are no guide.

But by the end a number of general insights shine through. The central one is that we have to think of both physics and consciousness in terms of networks and relations. You can’t find consciousness in single neurons, no matter how hard you look. The reductive approach, which seeks to break down phenomena to their smallest parts, doesn’t work for everything. The clearest evidence of the limits of reductionism is quantum entanglement, or “spooky action at a distance,” the title-phrase of Mr. Musser’s previous book. This is the phenomenon by which two particles appear to affect each other even though they are too far apart for any information to pass between them without exceeding the speed of light, a physical impossibility. No explanation of this oddity is possible if we focus reductively on the particles as discrete entities. Instead we have to see them as interrelated.

Consciousness, too, seems to depend upon patterns of interconnectedness. For a while now researchers into artificial intelligence have realized that we can get nothing close to human reasoning if we have computers that follow only linear processes. AI took off when scientists started to create neural networks, in which processes are conducted in parallel, mimicking the brain’s capacity to run different processes at the same time in its many parts.

This insight led to the currently hottest theory in consciousness studies, integrated information theory, which holds that consciousness is essentially the result of information being kept in whole systems rather than in parts. Adherents even quantify the degree of this integration with the Greek letter phi, which, says Mr. Musser, “represents the amount of information that is held collectively in the network rather than stored in its individual elements.” The higher the value of phi, the more conscious the system is.

By the end of “Putting Ourselves Back in the Equation,” Carlo Rovelli emerges as the physicist who is on the hottest trail. For Mr. Rovelli, there are no independent, objective facts. Truth is always a matter of relations. We understand that New York is west of London but east of San Francisco. Mr. Rovelli argues that all physical properties are like this: Nothing is anything until it is related to something else. It’s an old idea, found in ancient Greek, Chinese and Indian philosophy, and scientists are discovering it anew.

Link to the rest at The Wall Street Journal