I used to love talking about free will. I was never a beer pong type of person in college; a good philosophical debate was more my style, and free will was especially fun since it ranges over a huge intellectual terrain. One minute, you’re talking about high concepts in neuroscience or quantum physics; the next, you’re on to everyday worries about drug addiction and manipulative algorithms. But over the years the fun has drained out of these discussions for me. They always seem to run in circles. It doesn’t help that free-will deniers tend to be absolutist and dismissive. Even Robert Sapolsky, a neuroscientist who has become the leading denier on the strength of his recent book Determined, complains about “those on ‘my side.’”

The deniers probably figure that they have an open-and-shut case. Your life choices don’t fall out of a coconut tree. There’s always a reason that you take the actions you do: your mental states, your brain mechanisms, your nature, your nurture. Those reasons can be hard to fathom, which is why the world needs therapists and forensic detectives. But they’re still there; that’s a basic supposition not just of science but of any form of rational explanation. So when Sapolsky, following Nietzsche, defines free will as a “causeless cause”—a supernatural break when you make a choice unconstrained by the past—and reminds us that science doesn’t do causeless causes, he really doesn’t need to add 400 more pages to belabor the point. Of course you don’t have free will in this sense. The concept is so incoherent that it is not even wrong, and if you are discussing this in your dorm late at night, please just go to bed already.

Those arguing for free will make a subtler case. The so-called compatibilists—modern heirs to the Stoics and David Hume who believe that our decisions respect both physics and human agency—agree that every action you take has a cause. For them, a free choice is not a causeless cause, but a caused one—specifically, one that is caused by you. You are yourself the product of earlier events, but that doesn’t negate your place in the causal chain. Your choice is yours if the causes that produce it flow through you.

Deniers naturally prefer their own definition of freedom and say it matches what the average person thinks of when they think of freedom. I admit that, with the way politics is going, I have lost any confidence in my ability to tell what the average person thinks. But I hazard a guess that what they have in mind is closer to compatibilism. If one prisoner admits to a crime openly while another confesses under duress, a denier sees no difference; both confessions are preordained. But a compatibilist says the second prisoner is acting against their will; their confession does not flow out of them as a person in any essential way.

Compatibilism invites all sorts of questions about what “you” are, whether there is any genuine openness to the future, and what kinds of decision-making qualify as free. And that’s what makes compatibilism the more intellectually interesting position. It opens up the debate rather than shut it down. You and your friends can polish off multiple beers talking about it. It brings back the joy.

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For me, the appeal of compatibilism is that it grapples with the central dilemma of free will. Despite knowing intellectually that all our decisions can be traced back to preceding causes, we feel free. Samuel Johnson summed it up in 1778: “All theory is against the freedom of the will; all experience for it.” Scientists aren’t supposed to like it if a theory contradicts observations. We’re supposed to cancel the theory or find fault with the observations. But maybe theory and observations are fine and the trouble is that we haven’t properly thought through how the two relate.

We formulate our theories by imagining the world from outside—an objective or observer-independent view. Yet we experience the world from within—as embedded observers. When these two viewpoints clash, we have what in my recent book Putting Ourselves Back in the Equation I call an “inside/outside problem.” And free will isn’t the only such case. The hard problem of consciousness is another: objective theories of physics and neuroscience have no place in them for subjective experience. Quantum physics, cosmology, causation, and the nature of time also involve a conflict between outside and inside views. Marcelo Gleiser, Adam Frank, and Evan Thompson have a recent book, The Blind Spot, about these sources of tension.

For instance, fundamental physics has no notion of time or change; it treats the world as an eternal four-dimensional block. The universe at this level just is. The proposition that ultimate reality is timeless goes back to the ancient Greek philosopher Parmenides, and today it falls under the rubric of the “problem of frozen time.” When physicists mash their theories together to try to create a single unified theory, the t variable representing time drops out of their equations. Harried parents and students taking exams probably wish time would drop out of their equations, too; our daily experience is of a very loudly ticking clock. Loath to deny either theory or experience, most theoretical physicists have sought to reconcile them as two equally valid views of the universe. What looks like a static block from the outside can look dynamic to a participant on the inside. By analogy, if you lay out all the frames of a movie at once, there is no action or narrative, but if you run it through a projector, you see each frame in succession and the story unfolds.

Philosopher Jenann Ismael, in her academic papers and 2016 book How Physics Makes Us Free, has articulated a parallel account of free will. The universe may lack free will from the outside view, yet have it on the inside.

One point she makes is that you will always perceive an openness to your decisions, for the simple reason that you don’t know what you will decide until you do decide. Go ahead and take a guess. Coffee, you tell yourself: “When I wake up tomorrow, I will have coffee rather than tea.” It won’t work because you could change your mind at any time up to the moment of truth. Your self-knowledge creates a loop that foils predictions. If you’re like me and an advanced A.I. or marketing algorithm tells you you’ll choose coffee, you’ll flip on the teakettle just to spite it. A number of scholars have proved this point using theorems from computer science. In general, it is impossible to predict what a computer program will do until you run it, and the same goes for our own thought processes.

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Ismael also analyzes the self. The self tends to get left out of free-will discussions. People say, “You have free will,” or, “You don’t have free will,” without elaborating on the “you” part of that. How is the self constructed? How do we situate it in the physical world? Ismael describes the self as a “causal hub” that processes prior events, deliberates over them, broods over them. This internal deliberation is what distinguishes humans, other life forms, and advanced A.I.s from simpler systems, which have no significant interiority. We’re not just reacting to present circumstances. The same person under the same circumstances might make a totally different choice. Deliberation entails freedom. If we knew what we were going to do, we wouldn’t need to turn it over in our heads.

Because of human psychology’s complexity, the causal factors for our decisions can be very tangled. Why a magnet picks up a paper clip is a fairly simple story involving magnetic fields and the alignment of particles. Why you pick up a paper clip is a whole drama that might involve a compulsive tidiness, a misbegotten youth, and a fetish for smooth aluminum wire. Even our most trivial choices are shaped by everything we have seen and done in our lives. Each of us brings together a different set of life influences. No one else does it quite like you do, which is why you can fairly claim that your decisions are yours.

Years ago, for an essay on free will, I came up with the Toddler Test. It was a variant on the famous Turing Test of computer science. Ask a toddler to do something, anything. He or she will say “no.” Ask something else, and again “no.” The answers are completely predictable and completely understandable to a child psychologist. From the outside perspective, then, we’d say the toddler has no free will. But toddlers say “no” precisely to exercise their own agency. They want to be free and, in that desire, they become free. They take charge not just of their spinach-eating and toy-picking-up habits but also of their own self-construction. From an early age, we are deciding what kind of people we want to be. We don’t just let the universe push us around.

To a god that stands outside the universe, all is fixed. I think this god probably envies our mortal perspective. It’s one thing to know everything that will happen. It is another to actually live it. The universe on the inside is infuriating but also suspenseful. Not knowing all the answers is frustrating, but it gives us purpose. So rather than saying free will doesn’t exist and calling it a day, I’ll gather a bunch of smart people around me, find ourselves a dark corner of a bar, and debate for as long as the music plays and the beer flows. ♦