“Our task is not to penetrate into the essence of things, the meaning of which we don’t know anyway, but rather to develop concepts which allow us to talk in a productive way about phenomena in nature.” -- Niels Bohr, on the task of physics
From ages past, men have wrestled with the nature of reality: specifically, whether reality, at its root, is the cosmic stew of matter and energy, the ethereal stuff of mind and spirit, or some combination thereof.
As early as the 6th century B.C., Heraclites and Parmenides took opposing positions on this age-old question. Heraclites believed that reality consisted of those things that change -- that is, things whose ephemeral manifestation is in the physical realm. This concept formed the basis of materialism, the naturalistic view that the physical world of matter and energy is all there is.
Parmenides, on the other hand, argued that what was real was that which didn’t change and, therefore, was eternal. He considered the material world, being in flux and transitory, to be unreal, and our sense perceptions of it illusionary. The Parmenidian paradigm is the foundation of idealism, the view that reality is grounded in the non-physical realm of mind, thought, or spirit.
The metaphysics of Parmenides greatly influenced the philosophy of Plato. In his Allegory of the Cave, Plato depicted the material world as a shadow pointing to the real world of ideas and “forms.”
But by the 17th century, Rene Descartes, influenced by the early Greek philosopher Pythagoras, proposed that reality was not of one, but two separate essences: the first of mind, and the other of body. The Cartesian concept, formally called “substance dualism,” held that the mental and physical were so substantially different in nature, that neither could be shown to be a form of, or be reduced to, the other.
Some modern dualists bought into the ancient Greek notion that the body, as well as all matter, was bad and corrupted and, thus, confined to Earth; whereas, the mind (and soul), being pure and incorruptible, existed in an immaterial, celestial realm.
Only a few years later, Benedict de Spinoza presented a twist to substance dualism, suggesting that the body and mind are different manifestations of a more basic and ubiquitous substance, like Spirit, the universal force, the divine mind, cosmic consciousness, or the transcendental self. This view of reality became known as “property dualism.”
Although Spinoza has been called the first modern pantheist, the germ of property dualism has junction points with some Pauline concepts, as reflected in Paul’s account of Christ, who “fills everything in every way,” and in his depiction of God, “who is over all and through all and in all.”
If you’ve hung on this far, you may be thinking that each of these views has some good supporting arguments and some not so good, and weighing them to decide which is correct. Or maybe you’ve concluded that they all fall short of describing reality, and you’re back to square one in the metaphysical quest. Interestingly, contrary to Niels Bohr’s lead-in quote, modern science holds some important clues.
The Commonsensical World
Everyday experience tells us that the world is made up of physical things: things that occupy a definite position in time and space; things that possess actual properties like size, shape, color, texture, mass, and velocity. Our experience also tells us that the law of cause-and-effect is alive and well: a pot boils when heated; a soccer ball moves when kicked; my eardrum rings when the sound of the cymbal crash reaches my ear. Conversely, we “know” that any effect on an object requires an action, or force, on that object.
During the Scientific Revolution, this commonsense knowledge received a shot in the arm, due in no small measure to Isaac Newton and his laws of motion and gravity. The intuitive concepts of physicalism and cause-and-effect became so entrenched that by the 19th century, scientist Marquis de Laplace boldly asserted that the universe was completely deterministic.
According to the clockwork model of Laplace, the future state of any object could be fully determined if its initial state, and all of the forces acting on it, were known. Laplace went so far as to suggest that the deterministic laws of science governed everything from falling apples to human behavior. (Laplace presaged modern-day philosophical naturalists who believe that materialistic processes are responsible for every phenomenon from eye color and the Aurora Borealis to human spirituality and sexual identity.)
As long as investigators were content in examining the macrocosm of the sensible world, all appeared well. But as researchers delved into the underlying microcosm, a shift of tectonic proportions began shaking the halls of scientific inquiry.
The first seismic movement occurred in 1900, about one hundred years after light was found to behave like waves. Max Planck was investigating the energy distribution of radiating heat when he discovered that electromagnetic radiation (including heat and visible light) was composed of infinitesimal packets of energy called quanta. Five years later, Albert Einstein reinforced Planck’s finding when he demonstrated that those tiny packets of energy also exhibited particle-like behaviors, like a spray of ordnance from a sub-atomic assault rifle.
In 1924 another startling discovery was made when French nobleman Louis de Broglie pondered the implications of Einstein’s theory of relativity. The mass-energy equivalence of special relativity (E=mc2), together with the wave-like properties of light, led de Broglie to theorize that material “things,” like electrons, also have a wave-like character.
DeBroglie’s hunch was validated three years later by a couple of experimenters at Bell labs. After directing an electron beam though a double-slit grating, Clinton Davisson and Lester Germer observed an extraordinary phenomenon on the electron-sensitive screen behind the grating: an interference pattern, the signature of wave interaction.
It is provocative that, similar to the mind-body dualism proposed by the 17th-century metaphysicists, early modern physicists were unraveling a dualistic characteristic of the physical world. The discovery of wave-particle duality suggests something both ethereal and material about physical nature. It could also hint to a more basic essence of matter and energy. But more on that later.
What was waving?
Let’s go back to the Davisson-Germer experiment. If Davisson and Germer were correct -- that particles behave like waves -- what was “waving”? The earliest clue came in 1927 after Werner Heisenberg discovered the “uncertainty principle.”
Contrary to the assertions of Laplace, Heisenberg discovered that inside the microcosm of nature, the exact states and positions of quantal entities, like the electron, cannot be fully known. In other words, the innermost stratum of nature was opaque to human investigation. That was a staggering blow to classical physics because it shattered the causal underpinnings of a clockwork universe.
Even more stunning was what unfolded when Heisenberg’s principle was combined with the quantum formulations of Erwin Schrödinger. That partnership led to the discovery that the electron does not occupy an exact location at any given time, but is instead spread out over time and space according to a probability function.
It turns out that what is “waving” is the electron itself, according to the probability of its being in a given position. As a result, the interference pattern of the Davisson-Germer experiment is the result of the electron passing through both slits at the same time!
Now if you are reading this and thinking, “This goes against everything I know about the real world,” take comfort -- you are in very good company. It was such findings that caused early quantum theorist Niels Bohr to remark, “If someone says that he can think about quantum physics without becoming dizzy, that shows only that he has not understood anything whatever about it.”
But hold onto your seats, because the nature of reality, as seen through the looking glass of the quantum world, gets “curiouser and curiouser.”
“’Can anyone hide in secret places so that I can not see him? . . . Do I not fill the heaven and earth?’ declares the Lord.”
Continued next time. . . .
Regis Nicoll is a freelance writer and a BreakPoint Centurion. His "All Things Examined" column appears on BreakPoint every other Friday. Serving as a men’s ministry leader and worldview teacher in his community, Regis publishes a free weekly commentary to stimulate thought on current issues from a Christian perspective. To be placed on this free e-mail distribution list, e-mail him at firstname.lastname@example.org.
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