Science journalist Dan Falk explores how scientists are determined (predetermined?) to answer an age-old question of free will.
You’re reading this sentence right now — but were you compelled to do so?
Most likely, you feel that you freely made the decision to read that sentence, and the rest of these words. That is, you exercised your free will.
That doesn’t mean every decision is equally free; at the very least, there can be restrictions on our freedoms. Someone living under a repressive authoritarian regime is less free than someone living in a flourishing democracy. A person of limited means may be less free in choosing what car to buy than a millionaire.
But these restrictions don’t seem to be absolute: In spite of the various forces that may constrain our actions, we generally feel we have at least some measure of free will.
But the amazing thing is, scientists and philosophers have not reached any kind of consensus about whether free will actually exists.
The usual argument against free will goes something like this: The universe is the way it is because of how it was immediately before the present moment, along with the laws of physics. If you drop a hammer right now, where will it be half a second from now? Closer to the floor, that’s where. The past determines the present; the present determines the future — or so the argument goes.
Ever since Einstein developed his theory of relativity in the early 20th century, physicists and philosophers have wondered if the entire history of the universe is something like a block, an unchanging four-dimensional lump in which we just happen to exist, imagining that we freely choose our actions when in fact there is no such thing as a “choice” at all. In this view, time itself — or at least the flow of time — is some sort of illusion. No time, no free will.
In her recent book Existential Physics, Sabine Hossenfelder, of the Frankfurt Institute of Advanced Studies, notes that the block universe idea, unfathomable as it may seem, “is compatible with all we currently know.”
You don’t have to be a physicist to be suspicious of free will. The latest assault on free will has come from Robert Sapolsky, a biologist and neurologist at Stanford whose latest book is titled Determined: A Science of Life Without Free Will. Sapolsky believes that our culture, our environment, and the laws of nature completely determine who we are and what we do. I mentioned that we sometimes feel constraints or restrictions on our freedom — well, Sapolsky believes it’s constraints and restrictions all the way down.
“I’ve spent forever trying to understand where behavior comes from, on the level of neurons, on the level of hormones, on the level of evolution and social organizations,” he told me when I interviewed him recently for a story in Nautilus. And in the end “what you see is that there’s absolutely no room for free will.”
Along with biologists like Sapolsky and physicists like Hossenfelder, we have philosophers like Eddy Keming Chen of the University of California, San Diego. He approaches the problem from a very different direction, but arrives at the same conclusion. His main concern is quantum mechanics. Quantum theory is famously full of probabilities; the outcomes of measurements are said to be indeterminate until an actual observation is made.
At first glance, this might seem to rescue physics from the clutches of determinism — the idea that the future is uniquely determined by the present, which in turn was uniquely determined by the past. But it may not be that simple — especially once one applies quantum mechanics to the entire universe (the field of quantum cosmology). Chen argues that what we know about quantum mechanics supports something called “strong determinism,” in which — as with the block universe idea — the universe has one unique history, starting from a single prescribed starting point. (The details are rather involved, but you can read more in my recent story in Scientific American or Chen’s own paper in Nature.)
Other philosophers, meanwhile, have reached a very different conclusion. For example, in her book How Physics Makes Us Free, Jenann Ismael of Johns Hopkins University argues that what we normally think of as “freedom” remains intact, in spite of what our constituent atoms and molecules may be doing.
In particular, she sees the fatalism suggested by the block universe as unfounded. Sure, we can (with some effort) imagine an entity that has a “God’s eye view” of all of space and time; to this entity, the past and the future spread out in a vast block, no part any more or less real than any other part. But so what? That is not our view, and as Ismael emphasizes, it is our very decisions and actions that cause the future to unfold as it does. (And for what it’s worth, surveys suggest that the majority of philosophers — just fewer than 90 percent of them — believe free will is real.)
So where do I stand? My own view is that philosophers like Daniel Dennett and other so-called “compatibilists” had it right all along.
Compatibilism holds that, roughly put, human freedom exists independently of the microscopic world that lurks below. Yes, we’re made of atoms; but the possible lack of free will at the atomic level doesn’t imply its absence up here. You also won’t find atoms having a sense of humour, or falling in love – it’s just the wrong place to look for such phenomena.
Having said that, I can see why the debate over free will stirs such passion — after all, exercising our free will (or what we imagine to be our free will) lies at the very heart of what it means to be human.
Dan Falk is a science journalist based in Toronto. His books include The Science of Shakespeare and In Search of Time. Follow him on X at @danfalk and on Instagram/Threads @danfalkscience.
