I’d like to propose a thought experiment — one that may transform your understanding of something you see every day. Thought experiments can change the world, or at least your understanding of it. Einstein’s great scientific breakthroughs started with a thought experiment, something like this one.
For our experiment, imagine how a mirror works. If you hold up a sign to a mirror, the text appears reversed from left to right, but not from top to bottom. If you look at your own image in a mirror and nod your head, your reflected image seems to move the same way, nodding vertically. But if you raise your right hand, your image seems to raise its left hand. If I raise your left hand, your image raises its right hand. Your mirror image seems flipped horizontally.
Think about how weird this is, that nodding is different from waving. A mirror seems to reverse left and right, but it doesn’t seem to reverse up and down. How does it know? When you answer “how,” you imagine how a mirror works, and you formulate a hypothesis.
When I did this, my own first hypothesis about “how mirrors work” was wrong. I thought maybe mirrors flip things horizontally because we have horizontal eyes and binocular vision. Simple experiments knock down that hypothesis: Close one eye, use a camera lens, turn your head on its side, and nothing changes in the reflection. The mirror still seems to treat the horizontal differently from the vertical.
To solve this puzzle, I had to step out of my own way of thinking and imagine the ways of light. The light is what’s changed by the mirror, after all. When the light reflects off the mirror, it undergoes a “symmetry transformation.” The key is that the light undergoes a reflective transformation that complex matter like your body cannot do; it doubles back on itself and inverts its direction.
The mirror doesn’t change the light’s side-to-side direction or its up-down direction; it changes its in-and-out direction. When you look in a mirror and see your nose, the light from the tip of your nose has doubled back on itself. Your real nose can’t do this; it would be squashed, but the light from your nose can. Your west hand is still on the west side of the mirror, and your east hand is still mirrored on the east, but the light going north and south has switched directions. The mirror doesn’t rotate anything – it reflects and transforms the north-south movement of the light.1
Because we mammals have bilateral symmetry, when you see your reflection, you stay in your own shoes mentally. You project your own material symmetry. You think there’s another body there, and that body must have rotated. You naturally imagine matter, not light, undergoing the symmetry transformation of rotation around its center. But that’s an illusion — the real transformation is the z-axis reflection of light.
Meditating on the God Who Is Light
God tells us to think of Him as we think of light. James 1:17 says God’s light is so full and pure that it does not even cast a shadow.2 Light is a natural symbol of transcendence because it behaves so differently from our material bodies, yet we need it to take even the simplest of steps. Light is also a symbol of truth because it shows us the true path and our true faces, which we cannot see in the darkness.
Therefore, what we know about light from science might tell us something about God. Light never decays, so light is the closest thing to eternal that we can touch in this universe. Light has no mass, yet it has momentum: light can make a pendulum move by shining on it. Light superimposes, so that its colors add to brightness, while matter always insists on its own place, so that its colors add to darkness. That darkness is not a presence of a thing in itself; it is really the absence of light. Depending on how you look at it, light will move like a particle or a wave, or sometimes it’s both! Light is the fastest creature in the universe — it cannot be outrun.3
Einstein figured much of this out by putting himself in light’s shoes, in his thought experiments that led to the theory of relativity. Light follows rules, and these laws of light govern its transmission, reflection, refraction, diffraction, absorption, and scattering. George MacDonald said that these physical “laws are the waving of [God’s] garments, waving so because he is thinking and loving and walking inside them.”4 No one has seen God, but we can catch the hem of his robe. We can catch a glimpse of his glory in the eternity, purity, and unsurpassable velocity of light. We even glimpse the trinity in light’s superimposability.
These glimpses were all summed up in Christ, the Creator, who took the form of a servant, a creature, and dwelt among us. God reached down to us as one who “was from the beginning, which we have heard, which we have seen with our eyes, which we have looked upon, and our hands have handled.” (1 John 1:1 NKJV) The One who said “Let there be light” took on matter. His material works, his work on the cross, to let us see who God is, precisely.
Receiving God’s Gifts of Light, Truth, and Identity
The brother of Jesus, James, speaks of the heavenly lights as one of many good gifts from God coming down from the Father. Another major gift from God, James mentions immediately following, is the word of truth. The light shows you the truth.
Later, James says you can’t just be a seer of this truth — you must be a doer. One scientist called this verse, James 1:22, the scientist’s favorite verse, because it says you can’t just think about a hypothesis, you have to do an experiment.5 James continues to say, if you don’t act, if you don’t test and experiment, you are in danger of forgetting who you are: “Anyone who listens to the word but does not do what it says is like someone who looks at his face in a mirror and, after looking at himself, goes away and immediately forgets what he looks like” (James 1:22-23 NIV).
C.S. Lewis writes of someone who forgets who she is, in Till We Have Faces. Queen Oruel occupies herself with her career, neglecting her real self. At this point, she says, “I locked Oruel up or laid her asleep as best I could somewhere deep down inside me; she lay curled there. It was like being with child, but reversed; the thing I carried in me grew slowly smaller and less alive.”6
But after many years, Oruel returns to her real self. This happens only after she does the work of writing a book. She says, “I could never be at peace again till I had written” this book. “It burned me from within. It quickened; I was with book, as a woman is with child.”7 Needless to say, she couldn’t call up ChatGPT. Oruel had to do the hard work of writing herself.
But that wasn’t enough. It’s only when Oruel rewrites her first draft that she turns and changes. Rene Girard said that every first draft is a lie, and we must redraft to find the truth.8 After cleaning house and throwing away her first drafts, Oruel moved toward the truth.
James repeats the word “blessed” from the Beatitudes, saying basically, “Blessed are those who see the truth,” who look “into the perfect law of liberty” (1:25). The Greek verb for “look into,” “parakypsas,” means “to gaze intently,” with effort, intensity, and work. Don’t just glance at this truth, James says, but peer into it, let it permeate every corner of your soul. The God’s Word Translation reads, “continue to study” these truths from God.
Haven’t you had some days when you were physically tired from studying? That’s because it’s real, physical, neuronal work to push bad ideas out and unify the good ideas. That’s what it takes to “look into the perfect law,” to “parakypsas.” This weird word is only found five times in the New Testament, three of those times in two resurrection chapters, Luke 24 and John 20. Peter, John, and Mary all three lean down and “parakypsas,” gaze through the open door of the empty tomb. Peter and John see folded graveclothes, but Mary sees something more: two angels, one at the head and one at the feet of the burial slab, like the cherubim on each side of the ark of the covenant. (John 20:12)
Looking doesn’t solve everything. At first, it feels worse. Mary turns, confused and crying. She sees someone – maybe it’s the gardener? She’s still thinking in earthly patterns, not in heavenly patterns. She sees only the surface of things and does not yet know the whole truth.
Then, Jesus calls her name, and she knows. She stands transformed by Love himself. Paul tells the Corinthians that “whoever turns to the Lord,” as Mary did at the empty tomb, is “mirroring the Lord’s glory … transformed into the same image, from glory to glory.”9
This transformation is a turning, like a symmetry transformation of light in a mirror — but it is more than that. It is like the chemical transformation when sodium and chloride, two toxic elements, combine to make something lifegiving, the salt of the earth – but it is more than that. It is like a new birth, the growth of a child in her mother’s womb — but it is still more than that.
God’s uncreated light is powerful enough to transform the mirror that receives it. Christ brought about new creations, and it echoes through all that is made.
This essay is adapted from the Faculty Address given at Seattle Pacific University’s Ivy Cutting Ceremony on June 6.10
Footnotes
- If the mirror is an XY plane, then the light has been transformed in the Z direction, flipping the sign of its trajectory in that dimension. Images of this can be found on my colleague Doug Downing’s blog:https://douglasadowning.wordpress.com/2018/03/02/what-really-gets-reversed-in-a-mirror-image/
- The English Revised Version and New Living Translation both imply this.
- You can try, but as you catch up to light, spacetime itself distorts!
- George MacDonald, Unspoken Sermons: Third Series (Longmans, Green, 1907), 62.
- Mark Peterson. “Dante’s Physics.” In The Divine Comedy and the Encyclopedia of Arts and Sciences: Acta of the International Dante Symposium, 13–16 Nov. 1983, Hunter College, New York, (John Benjamins Publishing Company, 2012), 173.
- Lewis, Till We Have Faces: A Myth Retold (Harvest, 1984), 226.
- C.S. Lewis, 247.
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Girard cited this as a key insight behind Desire, Deceit, and the Novel, and connects it to scripture in A Theater of Envy: “A writer’s greatness as a mimetic revealer inevitably entails, at some point in his career, a concrete coming to terms with the truth of the doubles, and this experience can occur only at his own expense, at a severe cost to his mimetic ego. To accede to the mimetic awareness that structures his works, he must discover his identity with the targets of his own satire; he must accept the collapse of whatever mythical difference mattered most in his personal system of self-justification. Not theoretically but in his own flesh, he must verify the literal truth of Paul’s words to the Romans.” (in Romans 2:1). Rene Girard, A Theater of Envy: William Shakespeare (St. Augustine’s, Indiana, 1991), 339.
- George MacDonald, Unspoken Sermons, 50.
- https://www.youtube.com/watch?v=AXiRv0_8G84
