Does The Universe Exist If We Aren’t There To Observe It? — According To Quantum Physics

“Those who are not shocked when they first come across quantum theory cannot possibly have understood it.” — Niels Bohr

It’s a commonplace notion to think that the universe exists ‘out there’ without us there to live in it and observe it.

However, in the realm of quantum physics, an observer independent universe is simply impossible.

Thinking about it rationally, the universe began billions of years ago and should exist on it’s own, irrespective of us. But experiment after experiment in quantum physics has shown that this may seem counter intuitive.

In the quantum world, observers play a significant and powerful role.

According to the theory of superposition, particles can exist in several places & states at once, however, when an observer comes into the picture, particles start appearing in different positions and states, breaking superposition.

The second you put an observer to observe a quantum system, it picks a specific location or state — breaking the superposition.

According to Discover Magazine’s post about physicist John Wheeler,

“The quest for an answer to that question inevitably entails wrestling with the implications of one of the strangest aspects of modern physics: According to the rules of quantum mechanics, our observations influence the universe at the most fundamental levels. The boundary between an objective “world out there” and our own subjective consciousness that seemed so clearly defined in physics before the eerie discoveries of the 20th century blurs in quantum mechanics.

When physicists look at the basic constituents of reality — atoms and their innards, or the particles of light called photons — what they see depends on how they have set up their experiment. A physicist’s observations determine whether an atom, say, behaves like a fluid wave or a hard particle, or which path it follows in traveling from one point to another. From the quantum perspective the universe is an extremely interactive place.”

“Wheeler was an early advocate of the anthropic principle, the idea that the universe and the laws of physics are fine-tuned to permit the existence of life. For the past two decades, though, he has pursued a far more provocative idea for an idea, something he calls genesis by observership. Our observations, he suggests, might actually contribute to the creation of physical reality. To Wheeler we are not simply bystanders on a cosmic stage; we are shapers and creators living in a participatory universe.”

The Classic Double Slit Experiment

I’ll try to explain the classic double slit experiment and John Wheeler’s delayed-choice experiment in simple terms without delving into intricate details.

Together both experiments basically suggest that the quantum particles like electrons and photons act like either a particle or a wave depending on how they are observed.

This is known in the world of quantum physics as wave-particle duality.

The classic double slit experiment, consists of a photon/electron gun or a particle gun, two slits, and a screen. Like shown in the image below.

There are two ways to perform the classic double slit experiment. With photon detectors present and without. Or in simple terms, the experiment is performed with an observer and without.

In the experiment, photon detectors are positioned right beside each slit.

When the photon detectors are present with observers observing them, the photons travel through either slit and hit the screen acting like particles.

As shown in the image below

However, when the detector is removed, something strange happens, and you get a different pattern of alternating light and dark bands which signify waves.

This means that the particles act like waves when they aren’t observed.

Wheeler’s Delayed-Choice Experiment Recreated In 2015

John Wheeler’s delayed-choice experiment, on the other hand, is built upon the classical model, without delving into the intricacies of the experiment, it basically asks the question, “at what point does a particle ‘decide’ to be a particle or a wave?”

His original apparatus for the experiment was made using mirrors and we didn’t have the technology to perform it back in 1978 when he theorized it, however, in 2015, physicists at the Australian National University, including Dr. Andrew Truscott successfully demonstrated Wheeler’s delayed choice experiment using helium atoms scattered by laser light.

Truscott and his team converted a hundred helium atoms into a state known as the Bose-Einstein Condensate and ejected all the atoms until there was only one left.

They then used a system known as a ‘grating’ system to scatter the solitary atom using laser beams and used two gates to measure it.

So, the solitary helium atom would either act as a particle and pass through one slit or act as a wave and pass through both.

They then added a second grating system after the particle passed through the first gate to measure the exact state it was in.

With the second grating system, it showed interference and thus behaved like a wave. However, without the second grating system, the atom behaved like a particle and traveled through only one path.

Due to being measured at two gates, it meant that the atom hadn’t decided whether it would take the form of a particle or wave until the second measurement.

“The atoms did not travel from A to B. It was only when they were measured at the end of the journey that their wave-like or particle-like behavior was brought into existence,” said Trescott

The inference of the results suggest that the atom hadn’t ‘decided’ whether it would be a ‘wave’ or a ‘particle’ until the last measurement.

What This Means?

This experiment, theorized by Wheeler and all the experiments based on it since 2015 like the most recent ones in 2020 and 2021 suggest that the wave-like or particle-like nature of a particle cannot be decided unless and until the measurement or observation takes place.

This is in accordance to Niels Bohr’s view that it makes no sense to illustrate the wave-like or particle-like behavior of light and matter before the measurement happens.

Or in other words, without us being there to observe the particle, it cannot exist as either a wave or a particle.

This further explores the concept that without us, the universe would not exist, at least at the quantum level of atomic and subatomic particles.

How consciousness contributes to this experience is a topic for another day, and how time works at the quantum scale is also another topic that I will perhaps explore in further articles.

You can take a look at my earlier ‘Exploring Reality’ series of articles for the science behind how consciousness contributes to our living experience:

1. Exploring Reality(Part I): How We Perceive & Know The World Around Us
2. Exploring Reality(Part II): Evolution’s Argument Against Our Perceived Reality
3. String Theory: The History Of String Theory & How It’s The Closest Unified Field Theory We Know (Exploring Reality Part III)

But for the moment, this is a basic explanation of the question, “Does the universe exist if we aren’t there to observe it?”