Let me welcome you the same way Stewart welcomes Forest in Episode 7 of the Hulu miniseries Devs: with a lengthy, unattributed quote.

We may regard the present state of the universe as the effect of its past and the cause of its future. An intellect which at any given moment knew all of the forces that animate nature and the mutual positions of the beings that compose it, if this intellect were vast enough to submit the data to analysis, could condense into a single formula the movement of the greatest bodies of the universe and that of the lightest atom; for such an intellect nothing could be uncertain and the future, just like the past, would be present before its eyes.

Its a passage that sounds as if it could have come from Forest himself. But its not from Forest, or Katie, or evenas Katie might guess, based on her response to Stewarts Philip Larkin quoteShakespeare. Its from the French scholar and scientist Pierre-Simon Laplace, who wrote the idea down at the end of the Age of Enlightenment, in 1814. When Laplace imagined an omniscient intellectwhich has come to be called Laplaces demonhe wasnt even saying something original: Other thinkers beat him to the idea of a deterministic, perfectly predictable universe by decades and centuries (or maybe millennia).

All of which is to say that despite the futuristic setting and high-tech trappings of Devsthe eight-part Alex Garland opus that will reach its finale next weekthe series central tension is about as old as the abacus. But theres a reason the debate about determinism and free will keeps recurring: Its an existential question at the heart of human behavior. Devs doesnt answer it in a dramatically different way than the great minds of history have, but it does wrap up ancient, brain-breaking quandaries in a compelling (and occasionally kind of confusing) package. Garland has admitted as much, acknowledging, None of the ideas contained here are really my ideas, and its not that I am presenting my own insightful take. Its more Im saying some very interesting people have come up with some very interesting ideas. Here they are in the form of a story.

Devs is a watchable blend of a few engaging ingredients. Its a spy thriller that pits Russian agents against ex-CIA operatives. Its a cautionary, sci-fi polemic about a potentially limitless technology and the hubris of big tech. Like Garlands previous directorial efforts, Annihilation and Ex Machina, its also a striking aesthetic experience, a blend of brutalist compounds, sleek lines, lush nature, and an exciting, unsettling soundtrack. Most of all, though, its a meditation on age-old philosophical conundrums, served with a garnish of science. Garland has cited scientists and philosophers as inspirations for the series, so to unravel the riddles of Devs, I sought out some experts whose day jobs deal with the dilemmas Lily and Co. confront in fiction: a computer science professor who specializes in quantum computing, and several professors of philosophy.

There are many questions about Devs that we wont be able to answer. How high is Kentons health care premium? Is it distracting to work in a lab lit by a perpetually pulsing, unearthly golden glow? How do Devs programmers get any work done when they could be watching the worlds most riveting reality TV? Devs doesnt disclose all of its inner workings, but by the end of Episode 7, its pulled back the curtain almost as far as it can. The main mystery of the early episodeswhat does Devs do?is essentially solved for the viewer long before Lily learns everything via Katies parable of the pen in Episode 6. As the series proceeds, the spy stuff starts to seem incidental, and the characters motivations become clear. All that remains to be settled is the small matter of the intractable puzzles that have flummoxed philosophers for ages.

Heres what we know. Forest (Nick Offerman) is a tech genius obsessed with one goal: being reunited with his dead daughter, Amaya, who was killed in a car crash while her mother was driving and talking to Forest on the phone. (Hed probably blame himself for the accident if he believed in free will.) He doesnt disguise the fact that he hasnt moved on from Amaya emotionally: He names his company after her, uses her face for its logo, and, in case those tributes were too subtle, installs a giant statue of her at corporate HQ. (As a metaphor for the way Amaya continues to loom over his life, the statue is overly obvious, but at least it looks cool.) Together with a team of handpicked developers, Forest secretly constructs a quantum computer so powerful that, by the end of the penultimate episode, it can perfectly predict the future and reverse-project the past, allowing the denizens of Devs to tune in to any bygone event in lifelike clarity. Its Laplaces demon made real, except for the fact that its powers of perception fail past the point at which Lily is seemingly scheduled to do something that the computer cant predict.

I asked Dr. Scott Aaronson, a professor of computer science at the University of Texas at Austin (and the founding director of the schools Quantum Information Center) to assess Devs depiction of quantum computing. Aaronsons website notes that his research concentrates on the capabilities and limits of quantum computers, so hed probably be one of Forests first recruits if Amaya were an actual company. Aaronson, whom I previously consulted about the plausibility of the time travel in Avengers: Endgame, humored me again and watched Devs despite having been burned before by Hollywoods crimes against quantum mechanics. His verdict, unsurprisingly, is that the quantum computing in Devslike that of Endgame, which cites one of the same physicists (David Deutsch) that Garland said inspired himis mostly hand-wavy window dressing.

A quantum computer is a device that uses a central phenomenon of quantum mechanicsnamely, interference of amplitudesto solve certain problems with dramatically better scaling behavior than any known algorithm running on any existing computer could solve them, Aaronson says. If youre wondering what amplitudes are, you can read Aaronsons explanation in a New York Times op-ed he authored last October, shortly after Google claimed to have achieved a milestone called quantum supremacythe first use of a quantum computer to make a calculation far faster than any non-quantum computer could. According to Googles calculations, the task that its Sycamore microchip performed in a little more than three minutes would have taken 100,000 of the swiftest existing conventional computers 10,000 years to complete. Thats a pretty impressive shortcut, and were still only at the dawn of the quantum computing age.

However, that stat comes with a caveat: Quantum computers arent better across the board than conventional computers. The applications where a quantum computer dramatically outperforms classical computers are relatively few and specialized, Aaronson says. As far as we know today, theyd help a lot with prediction problems only in cases where the predictions heavily involve quantum-mechanical behavior. Potential applications of quantum computers include predicting the rate of a chemical reaction, factoring huge numbers and possibly cracking the encryption that currently protects the internet (using Shors algorithm, which is briefly mentioned on Devs), and solving optimization and machine learning problems. Notice that reconstructing what Christ looked like on the cross is not on this list, Aaronson says.

In other words, the objective that Forest is trying to achieve doesnt necessarily lie within the quantum computing wheelhouse. To whatever extent computers can help forecast plausible scenarios for the past or future at all (as we already have them do for, e.g., weather forecasting), its not at all clear to what extent a quantum computer even helpsone might simply want more powerful classical computers, Aaronson says.

Then theres the problem that goes beyond the question of quantum vs. conventional: Either kind of computer would require data on which to base its calculations, and the data set that the predictions and retrodictions in Devs would demand is inconceivably detailed. I doubt that reconstructing the remote past is really a computational problem at all, in the sense that even the most powerful science-fiction supercomputer still couldnt give you reliable answers if it lacked the appropriate input data, Aaronson says, adding, As far as we know today, the best that any computer (classical or quantum) could possibly do, even in principle, with any data we could possibly collect, is to forecast a range of possible futures, and a range of possible pasts. The data that it would need to declare one of them the real future or the real past simply wouldnt be accessible to humankind, but rather would be lost in microscopic puffs of air, radiation flying away from the earth into space, etc.

In light of the unimaginably high hurdle of gathering enough data in the present to reconstruct what someone looked or sounded like during a distant, data-free age, Forest comes out looking like a ridiculously demanding boss. We get it, dude: You miss Amaya. But how about patting your employees on the back for pulling off the impossible? The idea that chaos, the butterfly effect, sensitive dependence on initial conditions, exponential error growth, etc. mean that you run your simulation 2000 years into the past and you end up with only a blurry, staticky image of Jesus on the cross rather than a clear image, has to be, like, the wildest understatement in the history of understatements, Aaronson says. As for the future, he adds, Predicting the weather three weeks from now might be forever impossible.

The plot of this series is one that wouldve been totally, 100 percent familiar to the ancient Greeksjust swap out the quantum computer for the Delphic Oracle. Dr. Scott Aaronson, professor of computer science at the University of Texas at Austin

On top of all that, Aaronson says, The Devs headquarters is sure a hell of a lot fancier (and cleaner) than any quantum computing lab that Ive ever visited. (Does Kenton vacuum between torture sessions?) At least the computer more or less looks like a quantum computer.

OK, so maybe I didnt need to cajole a quantum computing savant into watching several hours of television to confirm that theres no way we can watch cavepeople paint. Garland isnt guilty of any science sins that previous storytellers havent committed many times. Whenever Aaronson has advised scriptwriters, theyve only asked him to tell them which sciencey words would make their preexisting implausible stories sound somewhat feasible. Its probably incredibly rare that writers would let the actual possibilities and limits of a technology drive their story, he says.

Although the show name-checks real interpretations of quantum mechanicsPenrose, pilot wave, many-worldsit doesnt deeply engage with them. The pilot wave interpretation holds that only one future is real, whereas many-worlds asserts that a vast number of futures are all equally real. But neither one would allow for the possibility of perfectly predicting the future, considering the difficulty of accounting for every variable. Garland is seemingly aware of how far-fetched his story is, because on multiple occasions, characters like Lily, Lyndon, and Stewart voice the audiences unspoken disbelief, stating that something or other isnt possible. Whenever they do, Katie or Forest is there to tell them that it is. Which, well, fine: Like Laplaces demon, Devs is intended as more of a thought experiment than a realistic scenario. As Katie says during her blue pill-red pill dialogue with Lily, Go with it.

We might as well go along with Garland, because any scientific liberties he takes are in service of the seriess deeper ideas. As Aaronson says, My opinion is that the show isnt really talking about quantum computing at allits just using it as a fancy-sounding buzzword. Really its talking about the far more ancient questions of determinism vs. indeterminism and predictability vs. unpredictability. He concludes, The plot of this series is one that wouldve been totally, 100 percent familiar to the ancient Greeksjust swap out the quantum computer for the Delphic Oracle. Aaronsonwho says he sort of likes Devs in spite of its quantum technobabblewould know: He wrote a book called Quantum Computing Since Democritus.

Speaking of Democritus, lets consult a few philosophers on the topic of free will. One of the most mind-bending aspects of Devs adherence to hard determinismthe theory that human behavior is wholly dictated by outside factorsis its insistence that characters cant change their behavior even if theyve seen the computers prediction of what theyre about to do. As Forest asks Katie, What if one minute into the future we see you fold your arms, and you say, Fuck the future. Im a magician. My magic breaks tram lines. Im not going to fold my arms. You put your hands in your pockets, and you keep them there until the clock runs out.

It seems as if she should be able to do what she wants with her hands, but Katie quickly shuts him down. Cause precedes effect, she says. Effect leads to cause. The future is fixed in exactly the same way as the past. The tram lines are real. Of course, Katie could be wrong: A character could defy the computers prediction in the finale. (Perhaps thats the mysterious unforeseeable event.) But weve already seen some characters fail to exit the tram. In an Episode 7 scenewhich, as Aaronson notes, is highly reminiscent of the VHS scene in Spaceballswe see multiple members of the Devs team repeat the same statements that theyve just heard the computer predict they would make a split second earlier. They cant help but make the prediction come true. Similarly, Lily ends up at Devs at the end of Episode 7, despite resolving not to.

Putting aside the implausibility of a perfect prediction existing at all, does it make sense that these characters couldnt deviate from their predicted course? Yes, according to five professors of philosophy I surveyed. Keep in mind what Garland has cited as a common criticism of his work: that the ideas I talk about are sophomoric because theyre the kinds of things that people talk about when theyre getting stoned in their dorm rooms. Were about to enter the stoned zone.

In this story, [the characters] are in a totally deterministic universe, says Ben Lennertz, an assistant professor of philosophy at Colgate University. In particular, the watching of the video of the future itself has been determined by the original state of the universe and the laws. Its not as if things were going along and the person was going to cross their arms, but then a non-deterministic miracle occurred and they were shown a video of what they were going to do. The watching of the video and the persons reaction is part of the same progression as the scene the video is of. In essence, the computer would have already predicted its own predictions, as well as every characters reaction to them. Everything that happens was always part of the plan.

Ohio Wesleyan Universitys Erin Flynn echoes that interpretation. The people in those scenes do what they do not despite being informed that they will do it, but (in part) because they have been informed that they will do it, Flynn says. (Think of Katie telling Lyndon that hes about to balance on the bridge railing.) This is not to say they will be compelled to conform, only that their knowledge presumably forms an important part of the causal conditions leading to their actions. When the computer sees the future, the computer sees that what they will do is necessitated in part by this knowledge. The computer would presumably have made different predictions had people never heard them.

Furthermore, adds David Landy of San Francisco State University, the fact that we see something happen one way doesnt mean that it couldnt have happened otherwise. Suppose we know that some guy is going to fold his arms, Landy says. Does it follow that he lacks the ability to not fold his arms? Well, no, because what we usually mean by has the ability to not fold his arms is that if things had gone differently, he wouldnt have folded his arms. But by stipulating at the start that he is going to fold his arms, we also stipulate that things arent going to go differently. But it can remain true that if they did go differently, he would not have folded his arms. So, he might have that ability, even if we know he is not going to exercise it.

We should expect weird things to happen when we are talking about a very weird situation. David Landy, San Francisco State University professor

If your head has started spinning, you can see why the Greeks didnt settle this stuff long before Garland got to it. And if it still seems strange that Forest seemingly cant put his hands in his pockets, well, what doesnt seem strange in the world of Devs? We should expect weird things to happen when we are talking about a very weird situation, Landy says. That is, we are used to people reliably doing what they want to do. But we have become used to that by making observations in a certain environment: one without time travel or omniscient computers. Introducing those things changes the environment, so we shouldnt be surprised if our usual inferences no longer hold.

Heres where we really might want to mime a marijuana hit. Neal Tognazzini of Western Washington University points out that one could conceivably appear to predict the future by tapping into a future that already exists. Many philosophers reject determinism but nevertheless accept that there are truths about what will happen in the future, because they accept a view in the philosophy of time called eternalism, which is (roughly) the block universe ideapast, present, and future are all parts of reality, Tognazzini says. This theory says that the past and the future exist some temporal distance from the presentwe just havent yet learned to travel between them. Thus, Tognazzini continues, You can accept eternalism about time without accepting determinism, because the first is just a view about whether the future is real whereas the second is a view about how the future is connected to the past (i.e., whether there are tram lines).

According to that school of thought, the future isnt what has to happen, its simply what will happen. If we somehow got a glimpse of our futures from the present, it might appear as if our paths were fixed. But those futures actually would have been shaped by our freely chosen actions in the interim. As Tognazzini says, Its a fate of our own makingwhich is just to say, no fate at all.

If we accept that the members of Devs know what theyre doing, though, then the computers predictions are deterministic, and the past does dictate the future. Thats disturbing, because it seemingly strips us of our agency. But, Tognazzini says, Even then, its still the case that what we do now helps to shape that future. We still make a difference to what the future looks like, even if its the only difference we could have made, given the tram lines we happen to be on. Determinism isnt like some force that operates independently of what we want, making us marionettes. If its true, then it would apply equally to our mental lives as well, so that the future that comes about might well be exactly the future we wanted.

This is akin to the compatibilist position espoused by David Hume, which seeks to reconcile the seemingly conflicting concepts of determinism and free will. As our final philosopher, Georgetown Universitys William Blattner, says, If determinism is to be plausible, it must find a way to save the appearances, in this case, explain why we feel like were choosing, even if at some level the choice is an illusion. The compatibilist perspective concedes that there may be only one possible future, but, Flynn says, insists that there is a difference between being causally determined (necessitated) to act and being forced or compelled to act. As long as one who has seen their future does not do what has been predicted because they were forced to do it (against their will, so to speak), then they will still have done it freely.

In the finale, well find out whether the computers predictions are as flawless and inviolable as Katie claims. Well also likely learn one of Devs most closely kept secrets: What Forest intends to do with his perfect model of Amaya. The show hasnt hinted that the computer can resurrect the dead in any physical fashion, so unless Forest is content to see his simulated daughter on a screen, he may try to enter the simulation himself. In Episode 7, Devs seemed to set the stage for such a step; as Stewart said, Thats the reality right there. Its not even a clone of reality. The box contains everything.

Would a simulated Forest, united with his simulated daughter, be happier inside the simulation than he was in real life, assuming hes aware hes inside the simulation? The philosopher Robert Nozick explored a similar question with his hypothetical experience machine. The experience machine would stimulate our brains in such a way that we could supply as much pleasure as we wanted, in any form. It sounds like a nice place to visit, and yet most of us wouldnt want to live there. That reluctance to enter the experience machine permanently seems to suggest that we see some value in an authentic connection to reality, however unpleasurable. Thinking Im hanging out with my family and friends is just different from actually hanging out with my family and friends, Tognazzini says. And since I think relationships are key to happiness, Im skeptical that we could be happy in a simulation.

If reality were painful enough, though, the relief from that pain might be worth the sacrifice. Suppose, for instance, that the real world had become nearly uninhabitable or otherwise full of misery, Flynn says. It seems to me that life in a simulation might be experienced as a sanctuary. Perhaps ones experience there would be tinged with sadness for the lost world, but Im not sure knowing its a simulation would necessarily keep one from being happy in it. Forest still seems miserable about Amaya IRL, so for him, that trade-off might make sense.

Whats more, if real life is totally deterministic, then Forest may not draw a distinction between life inside and outside of his quantum computer. If freedom is a critical component of fulfillment, then its hard to see how we could be fulfilled in a simulation, Blattner says. But for Forest, freedom isnt an option anywhere. Something about the situation seems sad, maybe pathetic, maybe even tragic, Flynn says. But if the world is a true simulation in the matter described, why not just understand it as the ability to visit another real world in which his daughter exists?

Those who subscribe to the simulation hypothesis believe that what we think of as real lifeincluding my experience of writing this sentence and your experience of reading itis itself a simulation created by some higher order of being. In our world, it may seem dubious that such a sophisticated creation could exist (or that anything or anyone would care to create it). But in Forests world, a simulation just as sophisticated as real life already exists inside Devswhich means that what Forest perceives as real life could be someone elses simulation. If hes possibly stuck inside a simulation either way, he might as well choose the one with Amaya (if he has a choice at all).

Garland chose to tell this story on TV because on the big screen, he said, it would have been slightly too truncated. On the small screen, its probably slightly too long: Because weve known more than Lily all along, what shes learned in later episodes has rehashed old info for us. Then again, Devs has felt familiar from the start. If Laplace got a pass for recycling Cicero and Leibniz, well give Garland a pass for channeling Laplace. Whats one more presentation of a puzzle thats had humans flummoxed forever?

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Making Sense of the Science and Philosophy of Devs - The Ringer