For many people of a certain age, the original 1980s PBS series Cosmos was a major event—a stunning love letter to astronomy that provided a novel way of thinking about ourselves and our place in the universe. Neuroscientist David Eagleman counts himself among those moved by Cosmos. He sees it as a model for his ambitious PBS series, The Brain with David Eagleman, a six-hour exploration of what has been called the most complex object in the known universe, the gelatinous mass that, somehow, makes us who we are. Eagleman answered questions from contributing editor Gareth Cook about the new show, which premiered in October. A fuller version of the interview appears online in Mind Matters, which can be found at www.ScientificAmerican.com/mind-matters. An edited transcript follows.
Your first episode addresses the question of how the brain “creates” reality. Can you explain what you mean by this and what is so challenging about trying to answer it?
Consider that whole beautiful world around you, with all its colors, sounds, smells and textures. Your brain is not directly experiencing any of that. Instead your brain is locked in a vault of silence and darkness inside your skull. All it ever experiences are electrochemical signals coursing around through its massive jungle of neurons. Those signals are all it has to work with and nothing more. From these signals, it extracts patterns, assigns meaning to them and creates your subjective experience of the outside world. Your reality is running entirely in a dark theater. Our conscious experience of the outside world is one of the great mysteries of neuroscience: not only do we not have a theory to explain how private subjective experience emerges from a network of cells, we aren't even certain what such a theory would look like. In the series, I confront that mystery, among others, to give an indication of where the field is going and how this might get solved.
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Those of us who are not psychologists or neuroscientists generally go through the day imagining that we consist of a unitary, conscious self, making decisions as we go. What are some of the ways the series challenges this assumption?
Glad you asked: I've devoted a whole episode to the question of how we make decisions. In that hour, it becomes clear that you, as an individual, are not single-minded. Instead you are built of competing neural networks, all of which have their own drives and all of which want to be in control. This is why we're interesting and complicated. We can argue with ourselves, we can get mad at ourselves, we can make contracts with ourselves. Who exactly is talking with whom? It's all you, but it's different parts of you. In another episode entitled “Who Is in Control?” I tackle the question of how much control your conscious mind actually has, as opposed to all the rest of the brain activity that chugs along without your acquaintance or your ability to access it. Collectively, over the course of the six episodes, I hope that viewers will find their assumptions about actions, beliefs and reality put under the microscope.
The final show is called “Who Will We Be?” What was the motivation behind that episode, and what can we expect to learn from it?
I'm captivated by the ways that our technology is becoming married to our biology, thereby changing our trajectory as a species. I recently spoke about this issue at TED, where I unveiled a device we've invented in my lab to feed new information into the brain. This can expand the narrow human slice of perception. In the last episode, I extrapolate the technology-biology marriage into the distant future—exploring, for example, whether we can freeze your brain and thaw it out 1,000 years later to reboot you. Or whether we can circumvent biology altogether and run a full, detailed simulation of your brain in a computer—and whether that would be you. If any of this turns out to be possible, it would open up scenarios for space travel because the biology we come to the table with is not terribly useful for interstellar voyages. What's more, the future-looking question of whether we could someday live in a simulation circles back to a very old question, contemplated by philosophers from Zhuang Zhou to Descartes to the Wachowski siblings [in The Matrix]: How would we know if we were already living in a simulation?