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December 29, 2019 - February 6, 2020
Perception is not a window on objective reality. It is an interface that hides objective reality behind a veil of helpful icons. “But,” you ask, “if that speeding Maserati
What false assumption bedevils our efforts to unravel the relation between brain and consciousness? I propose it is this: we see reality as it is. Of course, no one believes
beauty, are in the eye of the beholder and inform us about fitness—not about objective reality.
In short, if genes get beauty wrong, they tend to go extinct.
A woman can tell, from a photo of a face, if a man is prone to cheat and divert resources to other women; cheaters tend to look more masculine, but not more attractive.23 Men are less able to discern female cheaters.
Evolutionary psychology reveals that our perception of beauty is an estimate of reproductive potential.
The term qualia is sometimes used by philosophers to refer to subjective, conscious experiences—
Marr claimed that our perceptions normally match reality, that our ideas-of-things correctly describe the things-in-themselves. As he put it in his 1982 book Vision: “usually our perceptual processing
Further reading
This raises the question: When does natural selection favor veridical perceptions over subjective perceptions? Marr answered: when organisms get more complex.
This argument fails because it forgets a simple point about fitness: according to standard accounts of evolution, although fitness payoffs depend on the true state of the world, they also depend on the organism, its state, its action, and its competition. Feces, for instance, offer big payoffs for hungry flies, but not for hungry humans. A hydrothermal vent, belching hydrogen sulfide at 80ºC into water a few kilometers deep, offers big payoffs for the Pompeii worm Alvinella pompejana, but hideous death to all but a handful of extremophiles. The distinction between a state of the world (say, a
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This is a key point. Fitness is no mirror of the world. Instead, fitness depends in complex ways on the state of the world, the state of the organism, and the frequencies of strategies.
reality. But that reality is utterly unlike our perceptions of objects in space and time. Such a conclusion may seem absurd. Surely it’s due
But experiments by the cognitive scientist Michael Webster reveal that it is an essential feature of all levels of perceptual processing.27 Change the perceptual environment, put on rose-colored glasses, and your senses quickly adapt to report relative payoffs in the new context; they efficiently encode information about fitness.
If Cohen is right, then the FBT Theorem has made a fundamental error at the very start. It does not tell us, up front, what the contents of perceptual experiences are—what our experiences say about the world. So the theorem cannot possibly tell us whether our perceptual experiences are veridical. The theorem was a fool’s errand from the start.
tradition, I invite you to explore a new metaphor of perception: each perceptual system is a user interface, like the desktop of a laptop. This interface is shaped by natural selection;
(ITP). That name is a bit rich for a mere metaphor, but I try in what follows to pay the promissory note.1
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 veridical—not to reveal or reconstruct objective reality—but to let us live long enough to raise offspring.
fitness game and elbow their way into the next generation. The FBT Theorem tells us that winning genes do not code for perceiving truth. ITP tells us that they code instead for an interface that hides the truth about objective reality and provides us with icons—physical objects with colors, textures, shapes, motions, and smells—that allow us to manipulate that unseen reality in just the ways we need to survive and reproduce. Physical objects in spacetime are simply our icons in our desktop.
So yes, if I see a rattlesnake writhing my way, I must take it seriously. But it doesn’t follow that there is something brown, sleek, and sharp of tooth when no one observes. Snakes are just icons of our interface that guide adaptive behaviors, such as fleeing.
payoffs. Objects are not preexisting entities that force themselves upon our senses. They are solutions to the problem of reaping more payoffs
only that my headache exists, not that it would exist even if unperceived. A headache that I don’t perceive is no headache at all. I wouldn’t mind that kind of “headache,” of course. But if you tell me that my migraine is not real because it doesn’t exist unperceived, I’m liable to become quite cross with you, and for good reason. My experiences are surely real to me, even if they don’t exist unperceived.
This molecule is vanillin. We perceive it as the delicious taste of vanilla. Who could have guessed? So far as I can tell, the taste of vanilla in no way describes that molecule. Indeed, no taste describes any molecule. Tastes are mere conventions. Yet tastes usefully inform our choices of what to eat, choices that could mean life or death.
an illusion is a perception that fails to guide adaptive behavior.
Scientific theories, couched in the language of objects in spacetime, are theories still bound to the interface.
see. ITP is saying something much deeper. It says that even though we can, with the help of technology, observe all these new things, we are no closer to seeing reality as it is.
If our senses were shaped by natural selection, then the FBT Theorem tells us we don’t see reality as it is. ITP tells us that our perceptions constitute an interface, specific to our species. It hides reality and helps us raise kids. Spacetime is the desktop of this interface and physical objects are among its icons.
Locality is the claim that physical objects cannot influence each other faster than the speed of light.
Whether or not quantum theory is, as Einstein claimed, incomplete, it is incompatible with local realism. Bell’s experiments have now been performed in multiple variations, and the predictions of quantum theory have been confirmed each time. We now have excellent evidence that local realism is empirically false, even if quantum theory is false or incomplete. This means that realism is false, or locality is false, or both are false. There is no happy choice here for Einstein, or for our normal intuitions.
Entanglement is also strange. Place two spinning tops side by side, and you can describe each top and its spin separately. But you can’t do that for two entangled electrons. They have to be described as though they were one indivisible object, no matter how distant they are from each other.
Kochen-Specker (KS) Theorem. It says that no property, such as position or spin, has a definite value that is independent of how it is measured.
property can have a definite value that is independent of how it is measured, is called “noncontextual realism.” The KS Theorem says that noncontextual realism is false.
This means I can be certain what value I’ll find, and yet that value is not an element of objective reality. Certainty about what you’ll see doesn’t imply it already exists. Einstein, Podolsky, and Rosen were simply wrong to claim
Quantum theory explains that measurements reveal no objective truths,
just consequences for agents of their actions. Evolution tells us why—natural selection shapes the senses to reveal fitness consequences for agents of their actions.
This belief is no surprise. Evolutionary biology, as we have discussed, assumes the objective reality of objects such as DNA and organisms. It is not obvious that the acid of universal Darwinism—in the form of the FBT Theorem—dissolves this extraneous assumption and reveals that “more or less accurate symbolic representations of external reality” are never more fit than representations that hide external reality and encode fitness payoffs.
We don’t, according to Wheeler, passively observe a preexisting objective reality, we actively participate in constructing reality by our acts of observation.
is not confined to the subatomic realm. Wheeler’s delayed-choice variation on this experiment is clever: wait until after the photon passes the metal screen, and only then decide what to measure—path A, path B, or a superposition. In his words, “Let us wait until the quantum has already gone through the screen before we—at our free choice—decide whether it shall have gone ‘through
slits’ or ‘through one.’ ”26 Wheeler’s experiment has been performed with photons (and helium atoms!) and it works.27 What we choose to measure after the photon has passed the screen determines what the photon did, or at least what we can say about what it did, before we measured.
“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
information, not matter, is fundamental;
Observer complementarity is the statement that a fundamental description of Nature need only describe experiments that are consistent with causality.
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.”
“I am almost certain that space and time are illusions. These are primitive notions that will be replaced by something more sophisticated.”
six, that the amount of data you can store in a region of space depends on the area surrounding that region, not on its volume.
We live and move and have our being not in an objective reality of spacetime and objects, but in a data structure with a format of spacetime and objects, which happened to evolve in Homo sapiens to represent fitness payoffs in a manner that is frugal and useful.
How do shapes, colors, textures, and motions arise in the compression of fitness?
instead, an artificial sweetener); people who are more aerobically fit make shorter estimates of distance than those who are less fit. This suggests that our perception of a distance depends not just on the energy cost, but rather on the ratio of the energy cost to our available energy.5
It is counterintuitive, and belies our assumption that 3D space is an objective reality that our senses reconstruct. But it makes sense if you assume that our senses report fitness and need redundancy—such as an extra dimension of space—to ensure that their reports aren’t crippled by noise.
The picture that emerges is that spacetime and objects are a code used by our senses to report fitness.
If physical objects such as neurons have no causal powers, then IIT identifies consciousness with a fiction—not a promising move.
