When I was a teenager, I remember hearing the question “If a tree falls in the forest and no one is there to hear it, does it make a sound? At the time, I thought, “What a stupid question—of course it makes a sound.” But the longer I teach science, and the more I learn about our world at the quantum level, the less sure I am about the true nature of reality. Like Neo in The Matrix—do I want the blue pill or the red pill?
Of course, when a tree falls in the forest it sets up a series of pressure waves in the Earth’s atmosphere that when interacting with the tympanic membranes in our ear canals, initiates a series of events that ultimately generate electrical signals that travel along the auditory nerve to the brain which plays a sound. But if no one is there to interact with those pressure waves, then no – it doesn’t make a sound, because a sound is the result of an interaction—or perhaps better stated, a measurement.
As I write, I am looking out my office window at a Tabebuia tree, its pink and yellow1 trumpet-like flowers in full bloom. They’re gorgeous even though the pollen has my eyes itching, and I am sneezing.
But what is pink and what is yellow? The colors are caused by photons of light emanating from organic molecules in the flower petals that, upon absorbing sunlight, reemit that energy as predominately pink and yellow light. (The flowers are colorless in the dark.) The emitted photons are vibrating in the red and yellow portion of the visible electromagnetic spectrum. These wavelengths interact with my retinas to trigger a complex series of chemical reactions that ultimately produce an electrical signal along my optic nerve, which causes a movie to play in my brain of pink and yellow flowers gently blowing in the breeze.
I touch something and even with my eyes closed, I can sense whether it is sharp or smooth, hot or cold, wet or dry, round or square. Receptors in my skin send messages to my brain that activate a mental rolodex of stored images. The same case can be made for our sense of smell: Aromatic molecules alight on olfactory receptor neurons in the nose allowing us to distinguish thousands of different odorants.
What happens next after any sensory interaction with our surroundings is truly magical—a response—a memory is triggered, pleasant or otherwise. Our fight or flight instinct is switched on as we see and hear something that places us in imminent danger. Or perhaps, our response is something more banal: the aroma of roast chicken alerts me that my wife is cooking dinner, or a different sort of pungent odor suggests the dog has had an accident on the carpet again.
Apart from human interaction, reality is just a confluence of electromagnetic fields and invisible particles. In its harshest, most unfeeling characterization, reality is mostly empty space. It is, therefore, not so farfetched to conclude that the universe—with all of its unfathomable intricacies—can only be understood through human interaction and, therefore, was made for us to be appreciated as a fantastical, God-given gift.
It is by science-faith that I state my case, and I’m in good company with the writer of the book of Hebrews. He explained that the unseen things of this world could only be understood by faith, characterized not as intangible but as substantive and evidentiary: “the substance of things hoped for, the evidence of things not seen,” (Hebrews 11:1 KJV).
The Apostle Paul also understood this, writing in Romans that the “invisible things of him from the creation of the world are clearly seen, being understood by the things that are made, even his eternal power and Godhead; so that they are without excuse,” (Romans 1:20 KJV). Paul—the great theologian—waxing eloquent not just of the spiritual world but of quantum phenomena. And perhaps this is why the quantum world remains a mystery: It is there that the material intersects with the spiritual and can only be fully understood by both mind and heart—intellect and faith.
We humans, of course, are “the things that are made.” God has given us the ability to clearly see and understand the invisible things, even His “eternal power and Godhead.”
Clearly, we are without excuse.
My understanding is the point of first raising the question was that even if there were not people in the forest that God would hear the tree fall. That yes there had to be an observer, but that God, who knows everything, also observes everything, and it doing so provides the last link in the existence of phenomena in his world
Wonderful essay. Thank you.
It is not only humans who interact sensorially with the world — so your essay seems a tad anthropocentric.