"We shape the clay into a pot, but it is the emptiness inside that holds whatever we want"
Lao Tsu

But what is space?

"Not there the sun shines, nor moon nor star..."

But what is light?

From ancient times these questions have come down to us. How many minds have wondered about the nature of space and light? How many songs? How many hymns? In the 1700's Euler, the great mathematician, wrote to a German princess, "This is, beyond question, one of the most important inquiries in physics."

In the 1600's, with the help of a prism, Newton had separated sunlight into its constituent colors which he thought of as its "least parts". He thought of light as corpuscular. "Are not the rays of light very small bodies emitted from shining substances?" He thought that the colors were made by corpuscles of different sizes. The corpuscles were thought to travel as the planets travel, according to Newton's laws of motion. Left alone they traveled in straight lines.

For many years Newton's view swept the field. But why don't corpuscles collide?

Gradually at the hands of Huygens, Young, and Frensnel, Euler's notion that light might be a vibration like sound began to gain ground. But if light, like sound, was a wave motion, it required a medium for its transmission. Space could no longer be empty. Space must be filled with a material substance which came to be called the luminiferous ether.

But how could the ether be sufficiently rigid to transmit the vibrations at the speed of light and yet let the planets pass through it?

Then came Faraday with the discovery of electromagnetic induction. There were lines of force through space. There were electric and magnetic fields. Space was filled with fields, and the fields were filled with energy. There were gravitational fields and electromagnetic fields. And Maxwell suggested that light was an electromagnetic wave through space, through the luminiferous ether.

Then came Michelson and Morley. But no one could find the ether. Then came Planck and Einstein. Light, whether a wave or a particle, was quantized. And the energy of the quanta was Planck's constant times the frequency (E = hv). As Newton had suggested long ago, the color is related to the size (in this case energy) of the quanta. G.N. Lewis, who used the term "jiffy" for the length of time it takes light to cross a centimeter, called the quanta "photons". But the speed of the photons, with respect to the observer, is independent of the observer's motion through space. So Einstein thought that we could keep the photons, but who needs the ether? The photons, like fish out of water, were without the sea of the luminiferous ether in which to swim. But wait! Einstein put time into our geometry with space (where it belongs) so what does that do to our space? What we say now is that, "Matter tells space-time how to bend and space-time tells matter how to move" [Ref: Wheeler]. And, as Swami Vivekananda [a Vedantist monk and lecturer who visited the U.S. twice around the turn of the century] suggested to Tesla in the winter of 1895-96, that what we see as matter is just potential energy (E = m). Matter is wound up against space-time and space-time is wound up against [matter].

But what happens to our light?

In the four dimensional geometry of space-time we see things at a distance by seeing them in the past. The separation between the emission events and the absorption events of the photons goes to zero, and even the fish are gone. We are left with a universe which looks more like a dream. The separation between the perceiver and the perceived goes to zero because space and time come into Einstein's equation as a pair of opposites. (S=sqrt(x^2 - t^2), where x and t are the space and time separations between the two events, and S is the total space-time separation between those two events.) What we see as a light-year away, we see as a year ago, because the time comes in squared with a minus sign.

But what are the fields and what are the forces? What is the gravitational attraction, what is electricity, and what is inertia? And, what could exist in the absence of space and time?

Whatever exists in the absence of time must be the changeless, since change takes place only in time. And whatever exists in the absence of space must be infinite and undivided, since smallness and dividedness can only exist in space. But how does it show in space and time? Is gravity the undivided? And is love? Is electricity the infinite? And is our yearning for freedom? And is inertia the changeless, and is our yearning for peace? Are gravity, electricity, and inertia simply the underlying existence as we see it in space and time? Light has been reduced to the emission and absorption events and the photons are gone. Space and time have been reduced to a pair of opposites with zero separation between the perceiver and the perceived. So, the dream is in the dreamer, but the dream is alive, because the underlying existence shows through us in what we see.
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