Over the past 50 years, astronomers have made dozens of major discoveries that help explain the nature and origins of the universe. They’ve measured the cosmic microwave background, or leftover radiation from the Big Bang, with extremely high precision to help paint a picture of the first nanoseconds of the universe. They realized that the way galaxies were moving was being influenced by something invisible called dark matter that makes up roughly a quarter of the universe. And they discovered a new “ghostly” particle that passes through matter without much of a trace called the neutrino.
Scientists have continued to chip away at some of the fundamental questions about how the universe and its multitudes of parts work together, but they haven’t really gotten close to answering the most basic and elusive question that has been pursued by philosophers and scientists alike since human consciousness came to be: Why us, why here, and why now?
Or, as the late physicist Dr. John Wheeler said in an interview with Discover Magazine in 2002: “How come existence?”
“I’d be willing to have this arm cut off if I could understand how come the quantum? If I could understand how existence comes about,” Wheeler once said in a past interview. “I think it's a thing which is outside the bailiwick of lots of people, and yet I think it stands the most chance of giving a really dynamic impulse to the whole scientific enterprise.”
Wheeler was an ideological leader in developing quantum cosmology and is memorialized by his many contributions to the field, including coining the term black holes.
He was also known for his tendency to push the boundaries of what was possible in physics with creative ideas. “A lover of poetry and philosophy,” who “was acutely aware of the power of words to shape ideas,” wrote Richard Webb in a 2008 biographical piece published in Nature, Wheeler was “wont to write lectures on the blackboard simultaneously with both hands.”
"He was very taken with the thought that no phenomenon becomes a true phenomena until it has been observed."
One of his ideas, which he called the “participatory universe,” posits that our own observations could actually be what is creating our physical reality.
The idea could be depicted in a drawing of the letter “U,” where an observer stands on one column of the letter looking backward at the past history of the universe, said Dr. Bob Wald, a theoretical physicist at the University of Chicago who was Wheeler’s student at Princeton University between 1968 and 1972.
“He was very taken with the thought that no phenomenon becomes a true phenomena until it has been observed,” Wald told Salon in a video call. “The idea is that the past history of the universe has become definite when someone or people now are observing things about the past universe.”
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Wheeler was a legendary scientist that studied under Niels Bohr, who created the most widely recognized model for the atom called the Bohr model. Wheeler also worked closely with Albert Einstein, helping center his theory of general relativity. Known as a “physicist’s physicist” who worked on “ideas of ideas,” Wheeler inspired countless students over his nearly 50 years of teaching and encouraged their monumental discoveries. One of his students, Hugh Everett III, introduced the “many worlds” idea that suggests an infinite number of parallel universes exist.
“In Everett's mathematical formulation, these possibilities were coexisting and could come together and be extinguished,” Wheeler said in a past interview. “It was only when one got to the point where one had an irreversible act of observation that one of these became materialized … If there's anything designed to confuse somebody about what quantum mechanics is all about, this does it.”
Wheeler’s idea of the participatory universe is rooted in quantum mechanics, which allows a particle to be in two places at once by being in what is called a superposition state. This situation is demonstrated, for example, by the famous theoretical Schrödinger's Cat experiment, in which a cat is placed in a box with radioactive materials that could kill it. In this hypothetical example, the scientist observing the experiment wouldn’t know whether the cat lived or died until they opened the box. Therefore, two realities coexisted: The cat lived, and the cat died.
The famous “two-slit experiment,” demonstrated something similar but with photons. It found that these particles, which can either act like a particle or wave, acted as waves passing through both slits in the experiment when they were unobserved. However, when observed, they acted like particles passing through one slit or the other.
Wheeler also proposed his own “delayed choice” experiment. Whereas the two-slit experiment shows that observations before or during the experiment influenced its outcome, Wheeler’s experiment showed that delayed observations influenced the results of the experiment after the particles had already passed through the slits.
“One can decide, at the quantum level, whether an object shall go two routes to get to its final point or just one route,” Wheeler once said in an interview. “You can make the decision after it has already made the trip. That sounds like a contradiction, but it works.”
"They didn’t share his optimism that physics will be able to actually produce any theory of intelligibility and consciousness which is responsible for the physical picture of the world."
To put this idea into more tangible terms, said Dr. Andrei Linde, a professor emeritus at Stanford University who is one of the authors of the theory of the multiverse, recommends imagining opening the box with the Schrödinger's Cat with a three-day delay. The cat inside will either be dead or alive, making it seem like the outcome of the experiment was determined three days ago as expected and the observer registers the fact of what happened in the past, Linde said.
However, to be consistent with the many-world interpretation of quantum mechanics, one would need to ascribe certain reality to both outcomes and understand that the universe consisted of these two branches: one universe with a dead cat and one with a live cat.
"By observing the cat, we are learning in which one do we live," Linde said.
Wheeler’s idea of the participatory universe was initially seen as being a little too far out and was not pursued by the scientific community when he proposed it in the 1970s, said Dr. Alexei Nesteruk, a visiting lecturer and researcher in the philosophy of cosmology and quantum physics at the University of Portsmouth, England.
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“Many physicists did not like it because they called it impalpable and a little bit mystical,” Nesteruk told Salon in a phone interview. “They didn’t share his optimism that physics will be able to actually produce any theory of intelligibility and consciousness which is responsible for the physical picture of the world.”
After all, it changes the way we traditionally think about the way time works. Instead of the past causing the present, which causes the future, Wheeler’s idea flips this on its head to suggest that the future "determines" the past.
“This past becomes a construct of the human mind [working in the direction of] the future,” Nesteruk said. “This is a really interesting idea because it completely breaks down a naïve physical understanding of the past of the universe as the past of itself. It's not the past in itself. It's the past for us.”
However, the field’s initial rejection of the idea has started to change. In fact, an idea like the participatory universe that accounts for the role of the observer in determining something’s quantum state could help explain some mathematical conundrums that have appeared in quantum physics, Linde said.
“The question is really whether the unobserved universe makes any sense in physics if you would not include this consciousness,” Linde told Salon in a phone interview. “That is a far cry from what standard physicists would study, but Wheeler was not just any physicist.”
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