Back to: The Hermetic Laws & Quantum Physics
The Physics Revolution: When Reality Stopped Making Sense
The Clockwork Universe Before the Fall
To feel the shock of the quantum revolution, you have to inhabit the world it disrupted. By the end of the nineteenth century, classical physics had achieved a synthesis of staggering power and beauty. Newton’s mechanics described the motion of bodies from apples to planets with extraordinary accuracy. Maxwell’s equations, published in 1865, had unified electricity, magnetism, and light into a single electromagnetic theory. The kinetic theory of gases had connected thermodynamics to the statistical behavior of molecules. Chemistry had been tamed by the periodic table.
Embedded in this success was a particular picture of reality. Every object, at every moment, had definite properties. A precise position, a precise velocity, a precise energy, whether anyone was looking or not. The universe was deterministic: knowing the present state of a system precisely enough, combined with knowing the forces acting on it, was enough to predict its future with arbitrary accuracy. Pierre-Simon Laplace, in 1814, imagined an intellect that knew the position and velocity of every particle in the universe. Such an intellect, Laplace wrote, would see the future and the past laid out before it with the same clarity as the present. The observer was a separate thing from the observed, and the observer’s activities had no necessary effect on the world being observed. The universe was a great clockwork, and physics was the science of its gears.
I spent forty years in various positions as a technician and an engineer working within that picture, and I will tell you that it is an extraordinarily powerful framework. Most of the technology that runs your life, your car, your house wiring, your bridges and airplanes, depends on classical physics and only classical physics. The clockwork universe is not wrong in the domains where it applies. It is spectacularly right. What quantum physics revealed is that those domains, vast and successful as they are, are a special case within a much stranger reality.
The Three Cracks That Brought It Down
By the 1890s a handful of experimental phenomena had begun to resist classical explanation. Physicists at the time regarded them as loose ends, not crises. In hindsight, they were the early tremors of the revolution.
The first crack was blackbody radiation. When you heat an object until it glows, the spectrum of light it emits has a specific shape. Bright in the middle, darker toward both ends. Classical physics predicted that the spectrum should grow without bound as you went toward the ultraviolet end. The prediction was not slightly off. It was absurdly wrong. Since no oven in the world was pouring out infinite ultraviolet radiation, physicists called the problem the “ultraviolet catastrophe.” Planck’s 1900 quantum hypothesis, that energy can only be emitted or absorbed in discrete packets, resolved the catastrophe mathematically but at the cost of introducing a discontinuity into nature that nobody quite believed in at first, including Planck himself.
The second crack was the photoelectric effect. When you shine light on certain metals, electrons are ejected. Classical theory predicted that the energy of the ejected electrons should depend on the intensity of the light. It actually depends on the frequency. A very dim violet light ejects energetic electrons; a very bright red light may eject none at all. Einstein’s 1905 explanation required taking Planck’s quanta literally: light itself comes in discrete particles of energy whose energy depends on frequency, not intensity. This is the paper for which Einstein won the Nobel Prize in 1921, not his better-known work on relativity.
The third crack was atomic stability. By the early 1900s, experiments had established that atoms consist of a tiny dense nucleus orbited by electrons. Classical electromagnetism predicted that an orbiting electron should continuously radiate energy, spiral into the nucleus, and cause the atom to collapse in a fraction of a second. But atoms obviously do not collapse. Bohr’s 1913 model of the hydrogen atom postulated that electrons could only occupy specific discrete orbits, jumping between them in quantum leaps that emit or absorb precisely defined amounts of energy. This was not a derivation from classical principles. It was a break with them, introduced because the data demanded it.
The Quantum Revolution in Broad Strokes (1900-1930)
From these three cracks came the full-scale quantum revolution. The short version of a remarkable three-decade story runs like this.
1900: Planck introduces energy quantization to solve the blackbody problem.
1905: Einstein applies quantization to light in his photoelectric paper.
1913: Bohr builds the first quantum model of the atom.
1923: Louis de Broglie proposes that if light behaves sometimes as waves and sometimes as particles, matter itself must have an analogous wave aspect.
1925: Heisenberg, working with Max Born and Pascual Jordan, develops matrix mechanics, the first fully articulated mathematical theory of quantum behavior. Independently, Schrödinger develops wave mechanics, which Dirac and Schrödinger both soon demonstrate is equivalent to the matrix formulation.
1926: Max Born shows that the Schrödinger wave function gives probabilities for measurement outcomes, not a literal distribution of matter.
1927: Heisenberg publishes the uncertainty principle, establishing that certain pairs of observable quantities cannot be simultaneously known to arbitrary precision.
1927: Bohr articulates the complementarity principle at the Solvay Conference, framing what becomes the Copenhagen interpretation.
1928: Dirac publishes his relativistic wave equation for the electron and predicts the existence of antimatter.
1932: John von Neumann publishes Mathematical Foundations of Quantum Mechanics, establishing the rigorous operator-theoretic formulation and, in the process, raising the measurement problem in its sharpest form.
By 1932, the machinery was in place. It worked. It has gone on working, without significant modification, for nearly a century. The Standard Model of particle physics, developed from the 1960s onward, is a quantum field theory that extends this framework to all known elementary particles and three of the four fundamental forces. The anomalous magnetic moment of the electron has been predicted by quantum electrodynamics and measured experimentally to agree to roughly one part in a billion. There is no serious doubt that quantum mechanics is an accurate description of nature at the scales where it operates.
What Quantum Mechanics Actually Says vs. What People Think It Says
This is where the careful work begins. The fact that quantum mechanics describes a strange reality has made it an irresistible hook for all manner of claims it does not actually make. Let me separate the two categories as honestly as I can.
What Quantum Mechanics Actually Says
Quantum mechanics says that at the scale of atoms and subatomic particles, matter and energy are best described by a mathematical object called the wave function, usually denoted by the Greek letter psi. The wave function encodes the probabilities for the outcomes of any possible measurement on the system. Before measurement, the system is generally described as being in a superposition of multiple possible states. After measurement, the system is found in one definite state, with probabilities given by the square of the wave function’s amplitude (the Born rule). The behavior of quantum systems is governed by the Schrödinger equation, which is linear, deterministic, and continuous. Certain pairs of observable quantities, such as position and momentum, are subject to the uncertainty principle and cannot be simultaneously measured with arbitrary precision. Quantum systems can become entangled, meaning that measurements on spatially separated particles can exhibit correlations that cannot be explained by any local classical mechanism. This much is not controversial among physicists.
What Quantum Mechanics Does Not Say
Quantum mechanics does not say that thoughts create physical reality. Quantum mechanics does not say that conscious observation is required for the universe to exist. Quantum mechanics does not say that anything is possible if you believe hard enough. Quantum mechanics does not give you permission to manifest a car through the power of intention. These claims are not conclusions drawn from the theory. They are extrapolations, usually involving equivocation on the word “observer,” applied to scales and contexts where quantum effects do not meaningfully survive.
Module 5 of this course works through these misrepresentations in detail. For now, I want you to see something important: the fact that popular spirituality routinely overclaims from quantum mechanics does not mean that quantum mechanics has nothing interesting to say about consciousness and reality. It has something genuinely open to say. The measurement problem is real. The role of the observer is genuinely debated. Some serious interpretations of the theory do assign consciousness a constitutive role in the actualization of physical states. The honest picture, which this course will build patiently, is neither the New Age picture nor the dismissive skeptic’s picture. It is a third picture, more interesting than either, and it requires the tools we are about to develop.
Relativity and the Block Universe
One more piece of the physics story belongs in Module 0. Alongside quantum mechanics, the early twentieth century produced Einstein’s relativity. Special relativity in 1905 and general relativity in 1915. Relativity is a separate revolution from quantum mechanics, and it creates its own challenges to common sense.
Special relativity unified space and time into a single four-dimensional continuum called spacetime. Two observers moving relative to each other will, in general, disagree about the simultaneity of distant events, about durations, and about lengths, but they will agree about an underlying spacetime structure that is more fundamental than any of their individual measurements. General relativity then showed that gravity is not a force in the Newtonian sense but the curvature of spacetime caused by the presence of mass and energy.
The philosophical consequences are significant. One widely discussed implication of relativity is the so-called block universe, the view that past, present, and future are equally real aspects of a single four-dimensional structure, and that the passage of time may be more like an experiential feature of consciousness than a fundamental feature of reality. This is a contested interpretation among physicists and philosophers. It does, however, echo in striking ways some contemplative claims from the wisdom traditions about the illusory nature of time. We will return to this.
Why Physicists Argue About the Meaning of Their Own Equations
I want to close this section with a point that is easy to miss and essential to grasp. The mathematics of quantum mechanics is not in dispute. When Heisenberg wrote down the uncertainty principle, when Schrödinger wrote down his equation, when Dirac wrote down his, and when Born formulated the probabilistic interpretation of the wave function, they produced a set of tools that every physicist uses in essentially the same way. If you hand a quantum mechanics problem to a Copenhagenist, a Many-Worlder, a Bohmian, and a QBist, they will all compute the same answer. The experimental predictions are shared. The machinery is shared.
What is not shared is the picture of reality behind the machinery. Does the wave function describe something physically real? Or does it describe an agent’s state of information? Does the universe split into branches at every measurement event, or does only one outcome occur? Does consciousness play a role, or none? These are questions about what the equations are telling us, and physicists disagree about the answers because the equations do not force a unique answer. This is the interpretive problem. It is the philosophically deepest fact about modern physics, and it is the bridge between our two rivers. Without it, there would be no question about the relationship between Hermeticism and physics, because physics would have nothing to say about the topics Hermeticism cares about. Because of it, the question is genuinely open.