Light: More than meets the eye–a review of Grandy’s new book

Note: This is cross posted at By Common Consent.

“Perhaps you desire to know the manner in which God’s light is ascribed to the heavens and the earth—or, rather, the manner in which God is the light of the heavens and the earth in His own essence. It is not appropriate to keep this knowledge hidden from you, since you already know that God is light, that there is no light other than He, and that He is the totality of lights and the Universal Light.” Al-Ghazali, The Niche of Lights

We live in light. Before me now, the satiny white curtains of my living room have been transformed into a patchwork of bright silver where the morning sun strikes certain places in the fabric’s undulations. Darker areas (still colored white), are created in places where some of the vertical furrows of the drapes shy away from the radiance enjoyed by the alternating sunlit folds. These create striations and dappling that catch my eye and which I experience directly. I notice it more so this morning because I’ve been thinking about light. I want to write about light and I can’t help notice that I am surrounded by it. It fuses within me and although it is scattered around me, I cannot see it until it strikes my eye here in the center of my universe—I am an observer, a participant with light that creates my visual field and informs my consciousness. I experience light as it combines with my mind, integrating my world at a quantum level and then bubbling up into something that can be acted upon at macro scales.

Light. What is it?

I owe these contemplations to a new book by David Grandy, The Speed of Light: Constancy and Cosmos. Grandy is a philosophy professor at Brigham Young University where he teaches classes in the philosophy of science. This book, published by Indiana Press, is not written for Mormons per se, but one cannot read the book without recognizing that it has something profound to say to a people who have scriptures (D&C 88) that read:

6 He that ascended up on high, as also he descended below all things, in that he comprehended all things, that he might be in all and through all things, the light of truth;

7 Which truth shineth. This is the light of Christ. As also he is in the sun, and the light of the sun, and the power thereof by which it was made.

And

49 The light shineth in darkness, and the darkness comprehendeth it not; nevertheless, the day shall come when you shall comprehend even God, being quickened in him and by him.

50 Then shall ye know that ye have seen me, that I am, and that I am the true light that is in you, and that you are in me; otherwise ye could not abound.

Grandy begins by showing how, unlike the way we typically take the world such that light, in some sense, is moving through a fixed space and time, it is light that grounds the universe. It is the one constant, the framing structure to which space and time conform and to which they shape their warp and weave.

In this book, Grandy carefully unpacks the implications of the constancy of the speed of light by examining Einstein’s theory of relativity (the clearest explanation I’ve seen)*. But he does more than just catalogue light’s strangeness, he explores the stunning implications of that weirdness. He looks at the physics of light, its effect on space-time; he explores the uniqueness of light and the perplexing way it interacts with observers by affecting and being affected by them; he imagines how time passes for light, or more accurately put, how it is not affected by time’s passage; Grandy looks at ambient light in ways I’ve never thought of and explores the strange connectedness and disconnectedness of light as it moves beyond being both particle and wave; and lays out the case that light is fundamental in ways that we have just begun to discover. “Let there be light!” prior to all particular things (like suns), really is the right description of how our universe has unfolded. Or as Grandy puts it:

“ . . . light speed constancy is inclusive of, even, indistinguishable from, the first moment of creation, the originary event when spacetime bounds were set to what could and could not occur thereafter. I say “indistinguishable from” because, as noted earlier, time does not figure into light’s intrinsic nature.” p. 9.

However, for me the best parts of the book are the latter chapters where he explores the philosophies of Merleau-Ponty and Heidegger on the relationship between consciousness and light. These chapters, despite drawing from rather sophisticated ideas from Continental philosophy, are accessible and well explained. Consciousness and light seem to be part of a unified reality that for LDS readers will seem very familiar. This book was not written exclusively for Mormons, but members of our faith will find much to draw their interest in this book.

I typically read three or four books at the same time, but this one pushed everything to the side. I literally could not put it down. Grandy writes like an angel. My advice is not to start this book on a weekend in which you have things to do—because you will not get them done. Talk someone into putting this into your stocking.

I am sitting on a bench outside the church thinking about this book. The wind is blowing though the trees. Wind produced by the action of light from the sun on the atmosphere; trees fashioned by the action of light on photosynthetic cells drawing carbon out of the air and making trunk, branches, and the few remaining leaves clinging to the terminal sprigs; I close my eyes and listen to the sound of the wind rattling the leaves—a symphony produced by light in the form of wind and birch. I open my eyes to let this dancing light in. There, in the center of everything I experience the glissade of a light infused universe.

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Al-Ghazali, The Niche of Lights: A parallel English-Arabic text translated, introduced and annotated by David Buchman, 1998. Islamic Translation Series. Brigham Young University Press. Provo, UT.

*If you are riding on an airplane going 600 miles an hour and you walk 5 miles an hour toward the cabin. Someone on the ground would measure your speed at 605 mph. Right? But if you measure the speed of light in that same airplane it doesn’t matter whether it’s going toward the cabin or away. It always measures the same: 670,616,629 mph.