The brilliant Nicolas Berggruen invited me yesterday to lunch at Harvard Square on a beautiful sunny day and asked fundamental philosophical questions, among which: “What is your view on consciousness?”
In answering the question, I focused on the human brain because of my experience with Stephen Hawking. When Stephen visited my home in April 2016, he could only move his cheek muscles and eyebrows at will. Yet, he exhibited all the qualities that make us human. This experience made it clear that our brain, more than any other organ, defines what makes us human.
In my view, consciousness and free-will are emergent meta-level phenomena of complex cognitive systems. With its 100 billion neurons and up to a quadrillion synapses, the human brain encapsulates tremendous complexity which in combination with a rich and unpredictable environment, makes it impossible to forecast. The combination of a complex brain that responds to an undocumented environment introduces so many unmodeled degrees of freedom that the system behaves as if it has free will, whereas in fact it is simply unpredictable. The awareness of the brain to its environment manifests itself as consciousness. The level of consciousness must be degraded as the complexity is reduced down to the number of 3,016 neurons and 548,000 synapses in the brain of a fruit fly, whose wirings were fully mapped recently and where the response to the environment is more predictable.
The unpredictability of complex systems is enhanced by two fundamental facets of modern physics. One is chaos. In classical Newtonian physics, a two-body system admits an analytic solution that is fully deterministic. But adding a third body introduces chaos, in the sense that tiny deviations from a set of some initial conditions, could lead to huge differences in the outcome that grow exponentially over time. After many exponential growth-times, also labeled as the Lyapunov exponent, the state of a dynamical many-body system can be predicted only statistically based on various constraints. In a similar fashion, humans exhibit unique thoughts which are shaped by their experience with their environment. But when grouped in large societies, human behavior follows statistical patterns.
At a more fundamental level, the biological infrastructure of the human brain is rooted in quantum mechanical processes. The Heisenberg uncertainty principle, formulated in 1927 nearly a century ago, implies that the state of a quantum system cannot be defined precisely at any given time, including the position and velocity of each elementary particle. The chemistry of the brain is shaped by quantum mechanics, and this adds some unpredictability into its operation.
Our illusion of control in decision making is similar to the pride of drivers in the way they maneuver their cars. Self-driving cars, which are purely mechanistic systems with artificial intelligence, could be programmed to exhibit the qualities of our best human drivers given the constraints of the road. Frankly, I do not feel responsible for the functions of my brain in the same way that I had never touched the inner engine of the car that I bought from a dealer. For that reason, I do not take pride in the way I think.
Artificial intelligent (AI) systems are made of silicon and not flesh and blood. Even though they are our technological children, they could outsmart us in the same way that my two daughters can be smarter than I am.
As of now, Large Language Models (LLM) like ChatGPT, have neural networks with a number of connections that approaches the number of synapses in the human brain. Once they exceed this level of complexity, they will offer a testbed for examining my view that consciousness and free-will are emergent phenomena of complex cognitive systems.
Intelligence manifests the ability of a complex system to respond to its environment in an efficient way that avoids missteps characteristic of a random walk. Humanity might encounter superhuman intelligence on two fronts in the next decade: one in the form of human-made, artificial superhuman intelligence (ASI) and the second in the form of extraterrestrial superhuman intelligence (ESI). Humans might need to use ASI in order to understand ESI because the human brain might not be smart enough for the task.
Nicolas noted that it is possible that ESI is all around us but we fail to notice it. I admitted that even in the context of the material constituents of the Universe, we still do not understand what dark matter and dark energy are or what happened before the Big Bang or how to unify quantum mechanics and gravity in a predictive theory. This is related to the first question that Nicolas asked me: “What is the origin of existence?” to which I replied: “Perhaps the universe was created by a scientist who understood how to unify quantum mechanics and gravity.” Just as in the chicken and egg dilemma, each hen we know came from an egg that was laid by a hen. In the same way, our universe could have given birth to quantum-gravity engineers that will create baby universes which will make more quantum-gravity engineers, and so on. At any event, Nicolas and I agreed that there must have been something before the Big Bang
My hope is that one way or another, superhuman intelligence will bring humanity to a better place, or metaphorically speaking — the promised land of peace and prosperity. For that to happen, we need to use better role models than our politicians to guide us. In my book, these role models will come in the form of messengers from another star. Our traditional job description for God could be fulfiled by advanced science and technology.
At the end of our inspiring conversation, Nicolas asked me to write a message to his two children, Alexander and Olympia. I wished them to be the discoverers of our cosmic neighbors among the stars. As of now, we feel lonely in the cosmos. But as soon as we find a partner in interstellar space, the universe will not appear pointless anymore. My life’s purpose is to seek the company of a higher intelligence and I do not mind where it comes from.
ABOUT THE AUTHOR
Avi Loeb is the head of the Galileo Project, founding director of Harvard University’s — Black Hole Initiative, director of the Institute for Theory and Computation at the Harvard-Smithsonian Center for Astrophysics, and the former chair of the astronomy department at Harvard University (2011–2020). He is a former member of the President’s Council of Advisors on Science and Technology and a former chair of the Board on Physics and Astronomy of the National Academies. He is the bestselling author of “Extraterrestrial: The First Sign of Intelligent Life Beyond Earth” and a co-author of the textbook “Life in the Cosmos”, both published in 2021. His new book, titled “Interstellar”, was published in August 2023.
