Why did God make the world quantum rather than classical?

I saw the question “Why did God make the world quantum rather than classical?” in John Horgan’s Scott Aaronson interview in 2016. In that long interview Scott Aaronson takes great care to provide answers to Horgan’s questions.  The responses to his comments are listed here.

For those impatient readers, let me start with my short response. No single model or theory can explain all aspects of physical phenomena. We need a unique blend of different perspectives. That unique blend will certainly include quantum and classical physics perspectives but it may also include yet to be invented conceptual frameworks as well.

What do we mean by “quantum”?

Physicists have empirically (by physics experiments) demonstrated that matter is quantized. Humanity discovered the existence of biological cells. Then the existence of molecules and atoms were demonstrated. Experimental proof of electrons and photons were found much later. Many other elementary and composite particles were discovered also. It is clear that matter is composed of elementary components. This is one of the reasons physicists say “world is quantum” but there are other reasons.

Air is composed of molecules but it also behaves as a macroscopic entity (hurricane for example). The laws of the collective behavior can be quite different. We typically label the collective or macroscopic behavior with the adjective “classical” because those laws were discovered first. The laws of the microscopic components were discovered much later.

Matter is definitely quantized. Energy of an elementary particle is quantized too when that particle is confined to a region. For example, the energy of an electron bound to an atom is discrete (not continuous). Same is true for photons confined to a cavity. I should mention here for completeness that the energy of a free electron is continuous. In summary, energy may or may not be quantized.

We don’t know if space is quantized, or if time is quantized. These are open questions. I speculated in the past that space, time, and matter emerge simultaneously. If so, the space-time must be quantized because matter is quantized.

Secondary meaning of “quantum”

The word “quantum” also refers to experimentally verified effects of quantum entanglement, quantum superposition, quantum uncertainty and many other effects that cannot be explained by classical mechanics such as the Lamb shift, Casimir effect, and many other quantum phenomena including the Aharonov-Bohm effect.

The word “quantum” may also refer to Quantum Mechanics

In the literature the term “quantum” often refers to Quantum Mechanics which is the mathematical formalism that helps us model the quantum effects mentioned above.

What we mean by “classical”

Classical mechanics includes Newtonian dynamics, Einstein’s special and general relativity theories, thermodynamics, statistical physics, and some aspects of plasma physics and beam dynamics.

The word “classical” implies that in principle an infinite precision is possible in the measurement of physical quantities. In Quantum Mechanics this is impossible due to the uncertainty principle.

Classical Mechanics uses continuous variables. Most parts of Quantum Mechanics, on the other hand, use discrete variables.

Some physicists do not believe that world is “quantum”

Nobel laureate Gerard ‘t Hooft summarized his views on the quantum nature of the universe in a paper titled “The Cellular Automaton Interpretation of Quantum Mechanics: A View on the Quantum Nature of our Universe, Compulsory or Impossible” where he argues that at the most fundamental level (Planck scale) the world is classical. He argues that the quantum weirdness observed at the higher levels where we observe particles and fields can be explained by the loss of information. You can read the essential quotes from that paper here.

Classical/quantum distinction is rather prosaic

There are many posts in this blog site that talks about the temporary and partial confinement of Consciousness (ultimate reality, not the waking consciousness in humans) and its consequences. I don’t want to bore you with repetition. I will list few older posts here and quickly move on to the essential argument.

Confinement mechanisms in physics theories

Few Metaphysical Comments on Quantum Gravity

Confinement and Liberation (post)

Confinement and Liberation (page) (and the references therein)

I argued that Consciousness (ultimate reality) escapes the confinement of its own doing in myriad ways and the quantum nature is one of the escape (freedom seeking) mechanisms. I also argued that the two fundamental factors (Confinement or Binding Action) and (Liberation or Freedom Seeking) and their interplay modes can be used to build models of physical reality.

The binding action of is relentless. is singularity seeking. Elementary particles would be singularities without reaction which manisfests as quantum effects.

Without there would be no quanta, no charges, no discrete variables, no cognitive cores.

Without there would be no quantum effects, no waves, no forces, no interaction.

In the Confinement/Liberation perspective, classical/quantum distinction does not make sense. What matters is the Confinement/Liberation interplay which is the root cause of both the classical and the quantum effects.