Last month, scientists at Trinity College Dublin published research that the human brain may be a kind of quantum computer, rather than a classical one. This is a big, big deal.
Good science requires cautious and critical thinking. So it is no surprise that the specialty media outlets that covered this announcement did so in dry technical speak, not venturing to stretch far into the potential implications of the findings. Nor that the mainstream papers didn’t pick up on it, busy as they have been with the usual topics of war, Trump, Twitter, crypto implosions and the like.
Yet, buried in the cautious analysis in the Journal of Physics Communications paper is a discovery that could explain a range of profound dynamics of the human condition. That could give us hints that one day might change our entire understanding of how we relate to our species, or even to our place in the universe. Or universes.
Let’s start with three simple human experiences for context.
I have been here before, I know it
You visit a place and feel, with certainty, that you have been here before. This is such a common sensation the French came up with the phrase ‘déjà vu’ to describe it – the feeling that one has already lived through the present situation before. Somehow you know it matters to you, good or bad. Or you meet a person and you could swear you have met before, yet he or she is a total stranger. ‘You must have met in another life,’ is a popular colloquial explanation for a reason.
I live in the ‘what-if’
How many times have we found our minds wandering to past decisions and to the possible paths our life might have taken had choices been different? Our friends and family – and the legions of psychiatrists, therapists and coaches – tell us to forget all that and live in the moment. We are told it is neurotic to look back, to think about what might have been. Yet, you can’t help yourself. Sometimes it feels like you live in multiple states at the same time. Part of you is here, part somewhere else, sensing a different you living a different life. Why is the brain designed to fall into this seemingly self-sabotaging rut so easily?
I am in love
You connect with someone so deeply you feel helpless. You are in love, you think. It is chemical you hear from your friends. Yet, the connection does not have to be only between lovers. We all know siblings, perhaps identical twins, that claim with total sincerity to feel inextricably connected to the other. Or a parent to a child. Or even a human and an animal. We read stories of two people, separated by thousands of physical miles, who can physically feel when the other is in pain.
Classical computing vs quantum computing
We always have thought of the human brain as a classical computer. Put simply, this means we process one instruction at a time, like a computer that can consider a 0 or 1 in any moment but not both at the same time. To make computers super-fast, we load them up with more and more transistors and the power increases linearly. Nature seemingly did the same for our brains, putting around 86 billion neurons in our head, each acting like a kind of transistor for computation.
Out almost in the realm of science fiction (until recently) had been the idea of a quantum computer. Unlike its classical counterpart, a quantum machine doesn’t use transistors but rather qubits, which can represent both a 0 and a 1 at the same time.
To understand the importance of the word quantum ahead of the word computer, let’s step back and consider quantum physics for a moment. What we know (and there is a lot we don’t), is that quantum particles can move forward and backwards in time, exist in two places at once, and even teleport.
Superposition is a term that explains the quantum state where particles can exist in multiple states at the same time, and which enables a quantum computer to consider many different variables at the same time. Surely, we can all relate to this abstract idea. F. Scott Fitzgerald’s famous quote comes to mind, “The test of a first rate intelligence is the ability to hold two opposing ideas in mind at the same time and still retain the ability to function.”
Superposition is a doozy of a concept, but quantum entanglement is even more mind boggling. In simple terms, it means that if a tiny object like a particle is observed, even a long way away (light years), that particle will change its properties. It reacts to the watcher. Einstein dismissed this idea as ‘spooky action at a distance,’ but over time science has proved him wrong. And recently, we have learned that all kinds of objects interact with each other at a distance, even large ones like a satellite in space reacting to something on earth at the quantum level.
Quantum computing compared to classical computing is like the difference between two and three dimensions – no relevant frame of comparison. We have just begun assembling these quantum machines and already researchers have created devices so powerful they can do in minutes what it might take our best classical supercomputer 10,000 years. And the field is just starting, akin to where classical computing was in the 1980’s when the cutting-edge computers were large, slow and expensive mainframes had far less power than today’s watches. Yet, counter-intuitively, for some tasks classical computers will always be better. They have low error rates and can operate at room temperature. Quantum machines, on the other hand, must be kept ultra-cold (near absolute zero, or -460 degrees) and are moody like a teenager, with unpredictable error rates. They are magic, but for now they are also barely within our grasp.
What if there is a multiverse?
A number of years ago, through total circumstance, I found myself in conversation with Sir Martin Rees, the famous British cosmologist and astrophysicist. Martin is well known for many things, including that he has widely considered the likelihood of the multiverse, the idea that there might be more than one universe. I can vividly recall our exchange.
“So Dr. Rees”, I hesitantly and inarticulately asked, “After a life-time of study, how likely is it that there is more than one universe? How would you explain your view to a layman like me.”
“Let me put it this way,” the genial 80-something white-haired man with sparkling eyes said, “I could bet my dinner on it, I could bet my dog’s life on it, or I could bet my life on it. After considering this for over sixty years, I am somewhere between betting my dog’s life and my life.”
I love my dog like a child, and I said as much. Sir Martin smiled at me and said he felt the same. He was that sure.
And the number of possible other universes? Infinite.
How all this might fit together, in the quantum realm
For as long as humans have been self-aware, we have asked ourselves what is consciousness? How does it come about from neurons and synapses?
Back to those researchers at Trinity. Their analysis found quantum gravity at work in our brains, indicating that entanglement was also present. The implication may be that the white mass in our heads is not the classical computer we always thought it to be, but rather a kind of quantum machine. If so, it could help explain why our brains are so powerful.
And, it might also explain that feeling of déjà vu.
In the mind-bending landscape of quantum mechanics, where tiny particles get entangled and exist in multiple states at the same time, they form what can be thought of as a wave function. When we look at something, however, we see only one possibility of the particles. The rest collapse away, in the background of the reality we see.
In other worlds, however, a different quantum outcome becomes reality.
If our brains are indeed a kind of quantum computer, then perhaps consciousness comes from quantum entanglement. Perhaps, way out on the limb of speculation, we are entangled with others around us, and even with versions of ourselves from other universes, who have made different choices, and are living different lives.