This article addresses a deceptively simple question, what is reality? Our first response is to simply say look around you. Everything you see is part of reality. What’s wrong with that as an answer? Actually nothing is wrong with that answer if you’re trying to explain reality to a young child. As the child grows older, you will likely explain that reality also consists of things you can’t see as well, like radio waves. When the child goes to school, at some point they will teach the child about gravity and likely describe it as an invisible field between two masses that draws them together. The typical classroom lesson talks about Newton being hit on the head with an apple and as a consequence discovering gravity. So, if we sum up the typical description of reality taught to us as school children it consists of entities we can see and entities we can’t see.

Today we know that reality, our universe, is fundamentally made of mass and  electromagnetic energy (i.e., photons and electrons). We also know that even vacuums contain energy, which has been proven by laundry list of experiments, such as the Casimir-Polder force (i.e., an attraction between a pair of electrically neutral metal plates in a vacuum). Since Einstein’s special theory of relativity equates energy with mass via his famous equation E = mc^2, where E is energy, m is mass, and c is the speed of light in empty space, we can argue that the entire universe is made of energy in different forms. This should not surprise us since the most accepted theory of the universe’s evolution is the big bang theory. The big bang theory holds that the universe originated from an infinitely dense-energy point that expanded to form the universe we now observe.

From quantum mechanics we learn that all energy is quantized (i.e., made up of discrete packets of energy termed quantums). For example, light is made up of photons, and mass is made of atoms, which in turn is made of discrete subatomic particles, like protons and electrons. Although the science of physics breaks down when we attempt to model the infinitely dense-energy point that constituted the big bang at the point it came into existence, it’s logical to believe the energy that constituted the big bang must have also been quantized. However, this point should be considered a hypothesis, since it has not been proven.

What does all of the above say about reality? The answer is two points:

1. All reality is energy, which manifests itself in different forms
2. All energy is quantized (This is a fundamental pillar of quantum mechanics)

In a recent previous post, The Nature of Time Parts 1 and 2, I delineated that science holds that time itself is also quantized into small intervals termed Planck time. I also presented a conjecture that movement in time was related to energy. Please see that post for a more complete understanding. If you are willing to accept that all reality (mass, space, time, and energy) is composed of discrete energy quantums, we can argue we live in a Quantum Universe (i.e., a universe that is made up of discrete quantum of energy, including for example photons, atoms, subatomic particles, etc.).

I would like to add that this view of the universe is similar to the assertions of string theory, which posits that all reality consists of a one-dimensional vibrating string of energy. I intentionally chose not to entangle the concept of a Quantum Universe with string theory. If you will pardon the metaphor, string theory is tangled in numerous interpretations and philosophical arguments. No scientific consensus says that string theory is valid, though numerous prominent physicists believe it is. For these reasons, I chose to build the concept of a Quantum Universe separate from string theory, although the two “theories” (actually hypotheses) appear conceptually compatible.

A Quantum Universe may be a difficult theory to accept. We do not typically experience the universe as being an immense system of discrete packets of energy. Light appears continuous to our senses. Our electric lamp does not appear to flicker each time an electron goes through the wire. The computer you are using to read these words appears solid. We cannot feel the atoms that form the computer. This makes it difficult to understand that the entire universe consists of quantized energy. Here is a simple framework to think about it. When we watch a motion picture, each frame in the film is slightly different from the last. When we play them at the right speed, about twenty-four frames per second, we see, and our brains process continuous movement. However, is it? No. It appears to be continuous because we cannot see the frame-to-frame changes.

In summary, this article argues the nature of reality, the universe, consists of energy and that energy is quantized, resulting in a Quantum Universe.