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We survive because reality may be nothing like we think it is

Cognitive scientist Donald H. Hoffman asserts that not only do we invent our own personal views of reality, it’s an evolutionary necessity.

personal reality
Personal reality (ROBERT MEEKS/BILL SUTTON)

Professor of cognitive science at the University of California, Irvine Donald H. Hoffman, has doubts that reality is much like what we think it is. We live in a mental construction, he says, a sort of utilitarian fantasy, of our own devising. And it's not a problem that it may not be a true representation of reality — in fact, it may be evolutionarily necessary.

His study, “Natural selection and veridical perceptions" concludes, among other things, that “perceptual information is shaped by natural selection to reflect utility, not to depict reality."

Regular readers of Big Think may recall others, such as Alva Noë, declaring that our minds build our worlds. As Noë notes, what we see is light reflected off objects, not the objects themselves. Who knows what grass really looks like? We just know it's something that absorbs all colors except green. When an object creates a fluctuation in air pressure that travels through that medium to our ears where it excites tiny fibers, we hear that fluctuation as a sound. We can think of both examples as merely the mechanics of how we see and hear, but the fact remains, we don't directly perceive much. The world we think we live in is a story based on experiences we've had with these and our other senses. And since we don't see, say, electricity or WiFi signals, or colors or magnetic fields some other animals perceive, who knows what else is right under our noses? Logically, why would we assume that we see enough of reality to have a verdical understanding of it?

I am Mantis Shrimp. My rainbow's bigger than yours. (CHRISTIAN GLOOR)

Hoffman himself draws his conclusion about reality largely from quantum mechanics, where systems are only defined once they're observed. According to late physicist John Wheeler, “Useful as it is under ordinary circumstances to say that the world exists 'out there' independent of us, that view can no longer be upheld." Hoffman laments that people working in neurology and philosophy of mind often deliberately ignore advances in quantum physics. He tells The Atlantic that, “They are certain that it's got to be classical properties of neural activity, which exist independent of any observers—spiking rates, connection strengths at synapses, perhaps dynamical properties as well. These are all very classical notions under Newtonian physics, where time is absolute and objects exist absolutely. And then [the neuroscientists and philosophy of mind people] are mystified as to why they don't make progress."

Brain map (KY)

The “Natural selection and verdical perceptions" study was an answer to those who assert that if we weren't perceiving a real external reality, we'd have died out long ago. Hoffman's position, and this is supported by his study, is that building a functional worldview is in fact a prerequisite to survival — an image of the world that keeps one alive is more important than one that's objectively accurate. (If that's even on the table.)

The constructions we invent may not be literally true, but still, he says of his own, “I've evolved these symbols to keep me alive, so I have to take them seriously. But it's a logical flaw to think that if we have to take it seriously, we also have to take it literally." Of what he identifies as a snake or a train, he says, “Snakes and trains, like the particles of physics, have no objective, observer-independent features. The snake I see is a description created by my sensory system to inform me of the fitness consequences of my actions."

It's worth pointing out that if there can be no “public" objects that aren't personal constructions, science has a problem: “The idea that what we're doing is measuring publicly accessible objects, the idea that objectivity results from the fact that you and I can measure the same object in the exact same situation and get the same results — it's very clear from quantum mechanics that that idea has to go. Physics tells us that there are no public physical objects." After all, “My snakes and trains are my mental representations; your snakes and trains are your mental representations."

It's not that Hoffman considers our constructed personal realities therefore worthless. In fact, they're all we've got, and being real to us is a way of being true, after all. “I'm claiming that experiences are the real coin of the realm. The experiences of everyday life—my real feeling of a headache, my real taste of chocolate—that really is the ultimate nature of reality." And it's his and his alone.

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Exactly why or even how quantum tunneling happens is unknown: Do particles just pop over to the other side instantaneously in the same way entangled particles interact? Or do they progressively tunnel through? Previous research has been conflicting.

That quantum tunneling occurs has not been a matter of debate since it was discovered in the 1920s. When IBM famously wrote their name on a nickel substrate using 35 xenon atoms, they used a scanning tunneling microscope to see what they were doing. And tunnel diodes are fast-switching semiconductors that derive their negative resistance from quantum tunneling.

Nonetheless, "Quantum tunneling is one of the most puzzling of quantum phenomena," says Aephraim Steinberg of the Quantum Information Science Program at Canadian Institute for Advanced Research in Toronto to Live Science. Speaking with Scientific American he explains, "It's as though the particle dug a tunnel under the hill and appeared on the other."

Steinberg is a co-author of a study just published in the journal Nature that presents a series of clever experiments that allowed researchers to measure the amount of time it takes tunneling particles to find their way through a barrier. "And it is fantastic that we're now able to actually study it in this way."

Frozen rubidium atoms

Image source: Viktoriia Debopre/Shutterstock/Big Think

One of the difficulties in ascertaining the time it takes for tunneling to occur is knowing precisely when it's begun and when it's finished. The authors of the new study solved this by devising a system based on particles' precession.

Subatomic particles all have magnetic qualities, and they spin, or "precess," like a top when they encounter an external magnetic field. With this in mind, the authors of the study decided to construct a barrier with a magnetic field, causing any particles passing through it to precess as they did so. They wouldn't precess before entering the field or after, so by observing and timing the duration of the particles' precession, the researchers could definitively identify the length of time it took them to tunnel through the barrier.

To construct their barrier, the scientists cooled about 8,000 rubidium atoms to a billionth of a degree above absolute zero. In this state, they form a Bose-Einstein condensate, AKA the fifth-known form of matter. When in this state, atoms slow down and can be clumped together rather than flying around independently at high speeds. (We've written before about a Bose-Einstein experiment in space.)

Using a laser, the researchers pusehd about 2,000 rubidium atoms together in a barrier about 1.3 micrometers thick, endowing it with a pseudo-magnetic field. Compared to a single rubidium atom, this is a very thick wall, comparable to a half a mile deep if you yourself were a foot thick.

With the wall prepared, a second laser nudged individual rubidium atoms toward it. Most of the atoms simply bounced off the barrier, but about 3% of them went right through as hoped. Precise measurement of their precession produced the result: It took them 0.61 milliseconds to get through.

Reactions to the study

Scientists not involved in the research find its results compelling.

"This is a beautiful experiment," according to Igor Litvinyuk of Griffith University in Australia. "Just to do it is a heroic effort." Drew Alton of Augustana University, in South Dakota tells Live Science, "The experiment is a breathtaking technical achievement."

What makes the researchers' results so exceptional is their unambiguity. Says Chad Orzel at Union College in New York, "Their experiment is ingeniously constructed to make it difficult to interpret as anything other than what they say." He calls the research, "one of the best examples you'll see of a thought experiment made real." Litvinyuk agrees: "I see no holes in this."

As for the researchers themselves, enhancements to their experimental apparatus are underway to help them learn more. "We're working on a new measurement where we make the barrier thicker," Steinberg said. In addition, there's also the interesting question of whether or not that 0.61-millisecond trip occurs at a steady rate: "It will be very interesting to see if the atoms' speed is constant or not."

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