The Case Against Reality: Why Evolution Hid the Truth from Our Eyes

by Donald D. Hoffman

The blue icon does not deliberately misrepresent the true nature of the file. Representing that nature is not its aim. Its job, instead, is to hide that nature—to spare you tiresome details on transistors, voltages, magnetic fields, logic gates, binary codes, and gigabytes of software. If you had to inspect that complexity, and forge your email out of bits and bytes, you might opt instead for snail mail. You pay good money for an interface to hide all that complexity—all that truth, which would interfere with the task at hand. Complexity bites: the interface keeps its fangs at bay.

The language of the interface—pixels and icons—cannot describe the hardware and software it hides. A different language is needed for that: quantum physics, information theory, software languages. The interface helps you craft an email, edit a photo, like a tweet, or copy a file. It hands you the reins of the computer and hides how things actually get done. Ignorance of reality can aid c...

ITP claims that evolution shaped our senses to be a user interface, tailored to the needs of our species. Our interface hides objective reality and guides adaptive behavior in our niche. Spacetime is our desktop, and physical objects, such as spoons and stars, are icons of the interface of Homo sapiens. Our perceptions of space, time, and objects were shaped by natural selection not to be veri...

Perce...

Physical objects in spacetime are simply our icons in our desktop.

Physical objects are satisficing displays of crucial information about payoffs that govern our survival and reproduction. They are data structures that we create and destroy.

I must take my senses seriously. Must I therefore take them literally? No. Logic neither requires nor justifies this move.

ITP predicts another head scratcher: a spoon exists only when perceived. Ditto for quarks and stars.

Why? A spoon is an icon of an interface, not a truth that persists when no one observes. My spoon is my icon, describing potential payoffs and how to get them. I open my eyes and construct a spoon; that icon now exists, and I can use it to wrangle payoffs. I close my eyes. My spoon, for the moment, ceases to exist because I cease to construct it. Something continues to exist when I look away, but whatever it is, it’s not a spoon, and not any object in spacetime. For spoons, quarks, and stars, ITP agrees with the eighteenth-century philosopher George Berkeley that esse is percipi—to be is to be perceived.

Well, it makes no sense to pick one over the other. Sometimes, when you look, you see cube A, sometimes cube B. The answer must be that, when you don’t look, there is no cube—neither A nor B. Each time you look you see the cube you happen to construct at that time. When you look away, it goes away.

ITP says that the same is true for all objects in space and time. If you look and see a spoon, then there is a spoon. But as soon as you look away, the spoon ceases to exist. Something continues to exist, but it is not a spoon and is not in space and time. The spoon is a data structure that you create when you interact with that something. It is your description of fitness payoffs and how to get them.

Indeed, there is no need to posit any physical object, or a spacetime, that exists when no one observes. Space and time themselves are simply the format of our interface, and physical objects are icons that we create on the fly as we attend to different options for collecting fitness payoffs. Objects are not preexisting entities that force themselves upon our senses. They are solutions to the problem of reaping more payoffs than the competition, from the multitude of payoffs on offer.

I am inclined to reify my habit into an objective world. Why, I ask myself, do I keep seeing that spoon? Because, I tell myself, that spoon was there all along. Part of my logic is right. Something was there all along: my habit and an objective reality. But I’m wrong to assume that the objective reality is a spoon. I have made the mistake of reifying my habit into a preexisting spoon.

In like manner, I reify rocks, stars, and other icons in my interface, and pronounce them preexisting physical objects. I then reify the very format of my interface and fancy it to be a preexisting spacetime. This claim of ITP seems to agree with the philosophy of Immanuel Kant.4 Exegesis of Kant is notoriously controversial, but one interpretation has him claim that rocks and stars are not mind-independent. They exist entirely in our perceptions. Some philosophers find Kant’s claim troubling. Barry Stroud, for instance, says, “What we thought was an independent world would turn out on this view not to be fully independent after all. It is difficult, to say the least, to understand a way in which that could be true.”5 To understand a way in which that could be true, we simply need to understand evolution by natural selection. According to the FBT Theorem, if selection shapes perceptions, then perceptions guide useful behaviors rather than report objective truths about an independent world. Something exists independent of us, but that something doesn’t match our perceptions. This feels difficult to understand because of our penchant to reify our interface.

The examples of vanillin and Maseratis are, of course, just examples. They prove nothing about perception and reality. That’s the job of the FBT Theorem. But they may free us from our erroneous intuition that we see objective reality, and from our false belief that the moon is there when no one looks.

This is, of course, no argument that mathematics is an objective reality or that there are selection pressures for mathematical genius. It may be that such genius is a genetic fluke. Or perhaps sexual selection, in which the desires and choices of one sex shape the evolution of the other, can fan the flickers of basic mathematical skill into the flames of mathematical genius—a fascinating topic for research.

“But wait,” you might say, “there’s nothing new here. Ever since 1911, when Ernest Rutherford discovered that the atom is mostly empty space, with just a tiny nucleus at its center, physicists have told us that reality is quite different from what we see. That hammer may look solid but, if you look closely enough, you’ll find that it too is mostly empty space, with electrons and other particles whizzing about at incredible speeds.”

Well, not really. Those pixels are still on the desktop, still in the interface. They may not be visible without a magnifying glass, but they’re part of the interface nonetheless. Similarly, atoms and subatomic particles are not visible without special equipment, but they’re still in space and time, and so they are still in the interface.

ITP predicts that spacetime does not exist unperceived. My spacetime is the desktop of my interface. Your spacetime is your desktop. Spacetimes vary from observer to observer, and some properties of spacetime need not always agree across observers. Reality, whatever it might be, escapes the confines of spacetime.

ITP predicts that realism is false, and physics does not contradict this prediction. Instead, each test of local realism, in defiance of our intuitions, confirms the prediction of ITP. Experiments such as Zeilinger’s are tightening the noose around the neck of realism.

But noncontextual realism is precisely what we espouse in saying the moon is there when no one looks. It’s the realism that Francis Crick had in mind when he wrote that the sun and neurons exist when no one looks. It is this realism that is false—independent of any issues about locality.

The physicist Chris Fields discards noncontextual realism on different grounds. He shows that if no observer sees all of reality at once, and if observing takes energy, then noncontextual realism must be false.16 The physicists Chris Fuchs, David Mermin, and Rüdiger Schack claim that quantum theory entails “that reality differs from one agent to another. This is not as strange as it may sound. What is real for an agent rests entirely on what that agent experiences, and different agents have different experiences.”17 They explain, “A measurement does not, as the term unfortunately suggests, reveal a pre-existing state of affairs. It is an action on the world by an agent that results in the creation of an outcome — a new experience for that agent. ‘Intervention’ might be a better term.”

There is a world that exists even if I don’t look: solipsism is false. But my perceptions, like observations in quantum theory, don’t disclose that world. They counsel me—imperfectly, but well enough—how to act to be fit.

This confluence of physics and evolution has not been obvious. In 1987, William Bartley described a conference in which the physicist John Wheeler presented his take on quantum theory. Sir Karl Popper, a famous philosopher of science, “turned to him and quietly said: ‘What you say is contradicted by biology.’ It was a dramatic moment. . . . And then the biologists . . . broke into delighted applause. It was as if someone had finally said what they had been thinking.”

What did Wheeler propose that vexed the biologists? Wheeler claimed that, “What we call ‘reality,’ consists of an elaborate papier-mâché construction of imagination and theory filled in between a few iron posts of observation.”22 We don’t, according to Wheeler, passively observe a preexisting objective reality, we actively participate in constructing reality by our acts of observation. “Quantum mechanics evidences that there is no such thing as a mere ‘observer (or register) of reality.’ The observing equipment, the registering device, ‘participates in the defining of reality.’ In this sense the universe does not sit ‘out there.’ ”

No one really knows what a photon or electron does when both slits are open. This is an unsolved mystery of quantum theory. It seems incorrect to say it goes through A, through B, through both, or through neither. Physicists just say that its path is a superposition of A and B. This just means we don’t know what’s happening, even though we can write down simple formulas, involving linear combinations called superpositions, that accurately model the results of experiments. And it’s not just tiny particles, like photons and electrons, that do this magic with double-slits. In 2013, Sandra Eibenberger and her collaborators found the same magic feat performed by a large molecule—fondly called C284.H190.F320.N4.S12—consisting of 810 atoms, and weighing more than 10,000 protons or 18 million electrons. It is a tad smaller than a virus.25 Quantum weirdness is not confined to the subatomic realm.

No wonder that Popper and the biologists were nonplussed.

With this, we have the setup needed for a delayed-choice experiment on a cosmic scale. Using a telescope to capture photons from the Twin Quasar, we can choose to measure which path through the gravitational lens a photon takes—the upper or lower path in the Hubble image—or we can choose to measure a superposition. If we choose to measure its path and we discover, say, that it’s on the upper path, then for almost 14 billion years that photon has been on that path because of a choice we made today. If we had chosen instead to measure a superposition, then that photon would have a different history for the last 14 billion years. Our choice today determines billions of years of history. Most of us can’t bench-press a hundred kilos. But we can reach back billions of years and trillions of kilometers to rewrite the past—a Herculean feat.

We must spend more time on the delayed choice experiment!

This raises the stakes. Quantum theory smashed our intuitions about objects, by denying that they have definite values of physical properties that are independent of whether, or how, they are observed. Now it smashes space and time. As Wheeler put it, “No space. No time. Heaven did not hand down the word ‘time’. Man invented it. . . . If there are problems with the concept of time, they are of our own creation . . . as Einstein put it ‘Time and space are modes by which we think, and not conditions in which we live.’ ”

Wheeler’s jump from spacetime to bits of information is more than a bit jarring. Why should the two be related? And why should bits replace spacetime? Spacetime seems so real—indeed the very bedrock and framework of reality. Surely spacetime existed before there were bits, and surely bits exist inside spacetime, not vice versa?

Jacob Bekenstein and Stephen Hawking showed that the amount of information you can cram into a region of space is proportional to the area of the surface surrounding that space.32 That’s right, the area, not the volume. They first discovered this rule for black holes, but then realized it holds for any region of spacetime, not just regions containing a black hole. This rule is called the “holographic principle.”

We all have strong convictions about space and time. Mine were stunned by the holographic principle. But I soon realized that this result fits well with ITP, which says that spacetime, as you perceive it, is like the desktop of an interface. If you look through a magnifying glass at the desktop of your computer, you’ll see millions of pixels—the smallest patches of the desktop that are possible. Smaller than that, the desktop simply doesn’t exist. Step back, and it looks like a continuous surface. If you play a video game on your computer, such as Doom or Uncharted, you see compelling 3D worlds with 3D objects. Yet the information is entirely 2D, limited by the number of pixels on the screen. The same is true when you look away from your computer to the world around you. It too has pixels, and all the information is 2D.

The physicists Leonard Susskind and Gerard 't Hooft helped to pioneer the holographic principle. Susskind says, “Here, then, is the conclusion that 't Hooft and I had reached: the three-dimensional world of ordinary experience—the universe filled with galaxies, stars, planets, houses, boulders, and people—is a hologram, an image of reality coded on a distant two-dimensional (2D) surface. This new law of physics, known as the holographic principle, asserts that everything inside a region of space can be described by bits of information restricted to the boundary.”34 This principle is now widely embraced in theoretical physics. Observers have no access to “objects” in “space.” Observers only have access to information—bits—written on a boundary that surrounds space.

Einstein’s theory of general relativity says that a black hole sucks in and devours not just objects, but even space itself. As space gets sucked closer to the black hole, it flows faster, eventually reaching, and then exceeding, the speed of light. Nothing can travel through space faster than the speed of light. But that speed limit does not apply to space itself.

Where space pours into the black hole at the speed

of light, it is no longer possible for light, or information, to paddle upstream fast enough to escape. This is the event horizon of the black hole, the divide between the outside, where light can escape, and the inside, where escape is not possible. According to Einstein, a cat falling through the event horizon would, if the black hole is big enough, experience nothing unusual. Eventually, as the cat plunged toward the center of the black hole, it would be “spaghettified,” stretched beyond recognition by the rapidly changing force of gravity. But at the horizon it would just float on through, unaware that its fate was sealed. According to Einstein, the cat and all its information coast across the event horizon never to be seen again. Then, when the black hole evaporate...

But having the cat’s information in two places—inside and outside the black hole—violates another rule of quantum theory: quantum information can’t be copied. Not only is quantum information never destroyed, it can never be cloned. This is counterintuitive. I can copy information onto a hard drive. I can lose, or destroy, that drive. But my file consists of classical bits, which record classical information. Quantum information, however, is different from classical, and this raises the ante in the conflict between general relativity and quantum theory.

The classical premise of a unique primeval state for the universe is inapt: “if one does adopt a bottom-up approach to cosmology, one is immediately led to an essentially classical framework, in which one loses all ability to explain cosmology’s central question—why our universe is the way it is.”

This chapter began with the prediction of ITP that spacetime and objects do not exist unperceived; they are not fundamental reality. I asked whether this prediction has been ruled out by physics in its quest for a theory of everything (TOE). We have a clear answer: it has not. Instead, it has remarkable support.

Remarkably, a key prediction of ITP—that spacetime must go before a TOE will come—is close to consensus among physicists. Nima Arkani-Hamed, for instance, in a 2014 lecture at the Perimeter Institute, mentions that “Almost all of us believe that spacetime doesn’t exist, that spacetime is doomed, and has to be replaced by some more primitive building blocks.”

This

Planning and coordination are critical to our success. But do they require a veridical representation of objective reality? No, according to the FBT Theorem. Indeed, online games such as Grand Theft Auto let players collaborate toward ignoble goals, such as robbing stores or stealing cars. Their plans are informed not by veridical perceptions of transistors and network protocols, but by a fake world of fast cars and tempting targets.

The arguments for veridical perception fail. But it is still the standard theory in vision science. According to this theory, there really are 3D objects in spacetime with objective properties—such as shape —that exist even when no one looks. When you look at an apple, light bouncing off its surface gets focused by the optics of your eye onto your 2D retina. This optical projection of the apple onto your 2D retina loses information about the apple’s 3D shape and depth. So your visual system analyzes its 2D information and figures out the apple’s true 3D shape. It recovers, or reconstructs, the information lost by the optical projection. Sometimes this recovery process is called “inverse optics,” and sometimes “Bayesian estimation.”

It is also at odds with the truism that any system that undergoes a sequence of state transitions can be interpreted as a computer (perhaps a dumb one, but a computer nonetheless).

This prediction of ITP—that the appearance of causal interactions between physical objects in spacetime is a fiction—has interesting support from quantum computations that lack causal order.17 Normally we compute one step at a time, in a specific causal order. I might, for instance, start with the number ten, divide it by two, and then add two, to get the result seven. If I reverse the order, if I add two and then divide by two, I get the result six. The order of operations matters. But computers have now been built in which there is no definite causal order of operations. Instead the computer uses a superposition of causal orders, resulting in more efficient computation.

We will find a unified description for reality—animate and inanimate—once we take into account the limits of our interface. We will also find that networks of neurons are among our symbols for error-correcting coders.

You can think of the glowing line as your correction of an erasure. It’s as though your visual system decides that the actual message that was sent was a straight line, but that part of the line got erased in transmission. It corrects the error by filling in the gap with a glowing line. This is similar to error correction in a simple “Hamming” code that can send only two messages: 000 or 111.21 If the receiver gets, say, 101, then it knows that there was an error, that the middle 1 got erased, so it fixes the erasure and arrives at the message 111. This Hamming code uses three bits to send just one bit of information, so it allows the receiver to detect and correct one erasure error.

Recall that, according to QBism, a quantum state does not describe the objective state of a world that exists even if no one looks, but rather it describes the beliefs of an agent about what she will see if she acts, or, to put it more technically, what outcome she will obtain if she makes a measurement.

So you can get two different messages about a square from this figure. One message has the square in front, with glowing lines; the second message has the square in back, with lines that don’t glow. Notice that all four lines glow, or else all four lines do not glow. You never see, say, two lines glowing and two not glowing. Why? Because your visual system has united all four lines into a single unified message: a square. It has “entangled” the four lines into a single object so that what happens to one line must happen to all.

What we don’t see can, and sometimes does, kill us. But it usually does so only after we’ve raised offspring.