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A wild theory suggests that consciousness may explain quantum mechanics, by
forcing the subatomic particles to choose one concrete outcome.
One of the most perplexing aspects of quantum mechanics is that tiny
subatomic particles don't seem to "choose" a state until an outside observer
measures it. The act of measurement converts all the vague possibilities of
what could happen into a definite, concrete outcome. While the mathematics
of quantum mechanics provides rules for how that process works, that math
doesn't really explain what that means in practical terms.
One idea is that consciousness — an awareness of our own selves and the
impact we have on our surroundings — plays a key role in
measurement and that it's our experience of the universe that converts it
from merely imagined to truly real.
But if this is the case, then is it possible that human consciousness could
explain some of the weirdness of quantum mechanics?
Quantum measurement
Quantum mechanics are the rules that govern the zoo of subatomic particles
that make up the universe. Quantum mechanics tells us that we live in a
fundamental nondeterministic world. In other words, at least when it comes
to the world of tiny particles, it's impossible, no matter how clever
scientists are in their experimental design or how perfectly they know that
experiment's initial conditions, to predict with certainty the outcome of
any experiment. Know the force acting on a proton? There's no set location
where it's certain to be a few seconds from now — only a set of
probabilities of where it could be.
Thankfully, this indeterminism surfaces only in the subatomic world; in the
macroscopic world, everything operates according to deterministic laws of
physics (and no, we're not exactly sure why that split happens, but that's a
problem for a different day).
When physicists perform an experiment on quantum systems (for example,
trying to measure the energy levels of an electron in an atom), they're
never quite sure what answer they'll get. Instead, the equations of quantum
mechanics predict the probabilities of these energy levels. Once scientists
actually conduct the experiment, however, they get one of those results, and
all of a sudden the universe becomes deterministic again; once scientists
know the energy level of the electron, for example, they know exactly what
it's going to do, because its "wavefunction" collapses and the particle
chooses a certain energy level.
This flip from indeterminism to determinism is outright odd, and there is no
other theory in physics that operates the same way. What makes the act of
measurement so special? Myriad quantum interactions happen in the universe
all the time. So do those interactions experience the same kind of flipping
even when no one is looking?
The role of consciousness
The standard interpretation of quantum mechanics, known as the Copenhagen
interpretation, says to ignore all this and just focus on getting results.
In that view, the subatomic world is fundamentally inscrutable and people
shouldn't try to develop coherent pictures of what's going on. Instead,
scientists should count themselves lucky that at least they can make
predictions using the equations of quantum mechanics.
But to many people, that's not satisfying. It seems that there's something
incredibly special about the process of measurement that appears only in
quantum theory. This specialness becomes even more striking when you compare
measurement to, say, literally any other interaction.
For instance, in a faraway gas cloud, deep in the vastness of interstellar
space, nobody is around; nobody is watching. If, within that gas cloud, two
atoms bump into each other, this is a quantum interaction, so the rules of
quantum mechanics should apply. But there is no "measurement" and no result
— it's just one of trillions of random interactions happening every day,
unobserved by humans. And so the rules of quantum mechanics tell us that the
interaction remains indeterministic.
But if those same two atoms bump together inside a laboratory, scientists
can measure and record what happened. Because a measurement occurred, the
same rules of quantum mechanics tell us that the indeterminism flipped to
become deterministic — that's what allowed me to write down a concrete
result.
What's so different between these two cases? Both involve subatomic
particles interacting with other subatomic particles. And every step of the
measurement process involves subatomic particles at some level, so there
shouldn't be an escape from the usual quantum rules that say the outcome
should be indeterminate.
Some theorists, such as pioneering quantum physicist Eugene Wigner, point
out that the only difference between these two scenarios is that one
involves a conscious, thinking observer and the other does not. Thus, what's
called a "collapse" in quantum mechanics (the transition from
indeterministic probabilities to a concrete result) relies on consciousness.
Dreams of the universe
Because consciousness is so important to humans, we tend to think there is
something special about it. After all, animals are the only known conscious
entities to inhabit the universe. And one way to interpret the rules of
quantum mechanics is to follow the above logic to its extreme end: What we
call a measurement is really the intervention of a conscious agent in a
chain of otherwise mundane subatomic interactions.
This line of thinking requires consciousness to be different from all
the other physics in the universe. Otherwise, scientists could (and do)
argue that consciousness is itself just the sum of various subatomic
interactions. If that's the case, there's no end point in the chain of
measurement. And if so, then what scientists do in the laboratory really
isn't any different from what happens in random gas clouds.
While not strictly a physical theory, the concept of consciousness as
different and separate from the material universe does have a long tradition
in philosophy and theology.
However, until someone can figure out a way to test this concept of
consciousness as separate from the rest of the physical laws in a scientific
experiment, it will have to stay in the realm of philosophy and speculation.
This is part of an ongoing series describing potential interpretations of
quantum mechanics.
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Physics