Thursday, September 3, 2009

What Color is a Green Apple?

a parable of perception

Things aren’t always as they seem.

Take your favorite coffee cup and put it on the table in front of you. Now look at it. Let’s say for the sake of the argument that you have “normal,” non-corrected, 20/20, human eyesight. Your eyes are giving you information about the cup. Your image of it is sharp and clear. You assume that what you are seeing is the cup. But is it?

An enormous number of living creatures on earth have eyes. Elephants, eagles, dogs, hammerhead sharks, and houseflies all have eyes. But are their eyes identical? When other creatures look at your cup, do they see exactly what you see? Do they see shapes and colors the same way your eyes do? If not, then which image of your cup—the elephant’s, eagle’s, dog’s, shark’s, housefly’s, or yours—is “correct”? Which one is really the cup?

When you examine the problem this way, you begin to see that all of these images belong to the cup, but none of the images are the cup. The cup is a reality that is more than merely what your eyes can see. Your eyes only see a narrow band of the full spectrum of light. For example, your eyes can see no light from the ultraviolet or the infrared spectrums. Your eyes “see” the cup, for sure, but only in the spectrum of light that your eyes are designed with which to see.

What you see, your visual image of the cup, is limited by your eyes’ design. In fact, your eyes are sieves that filter out the chaotic light frequencies that interfere with your survival—so you can hunt a deer, spot a crouching lion, and avoid walking off a cliff. Therefore your image of the cup is incomplete. The cup’s cup-ness is more than what your eyes in their limitations can perceive.

When an apple appears green to you, it is not because the apple is actually green. The surface of the apple happens to absorb blue and red wavelengths of light while it reflects green. The apple then appears to your eyes to be green. But if you were significantly colorblind, you probably would not be able to tell a red from a green apple!

One in every 100 males has some “red-weakness” (Protanomaly), meaning shades of red are difficult to distinguish. Five in every 100 males has a “green-weakness” (Deuteranomaly). (Colorblindness in women is very rare. Tritanope is even rarer.) A colorblind person who looks at a colorful map of the world will see “the world” differently than you. The following four maps of the world demonstrate this.

When your eye sees the green apple, the really weird thing is that a green apple is actually absorbing every other color but green. Green is the only light wave that it rejects! Your eye sees the apple as green because green is the only light color it can’t keep (absorb).

To state this even more accurately and boldly, when you look at your cup, you’re not really seeing your cup at all. Your eyes are “reading” the light reflected off of the cup’s surface. If you put your cup in total darkness, the cup is still there even though you can’t see it. Does the cup exist in the dark? Yes, obviously. So your cup is more than its mere appearance. Cup-ness is a reality in and of itself apart from your visual perception of the light bouncing off of it. The fact that a blind person can drink from your cup should have told you that! The cup is more than meets the eye.

We are “seeing things” because of light. Eyes are organs that process light. Light enters the eye, shining on what are called cones and rods, and the light triggers a chemical reaction in the rods and cones, and the chemicals turn into electrical impulses that are sent to a certain part of the brain where these impulses are received, organized, and transmitted to other parts of the brain for analysis and communication.

So when you look at your cup, are you seeing your cup? Yes and no. “Yes” because the image your eyes provide is an actual image of your cup. “No” because the image is not your actual physical cup. Like a camera, your eye catches light and provides a “photograph” of that light bouncing off of stuff like your cup. Light bounces off of the cup and goes into your eyes, and you “see the light” bouncing off the cup. You do not see the cup itself. For everyday purposes everyone seems to assume that the cup they “see” is the actual cup. In a very real sense it’s not.


Because light is the only thing eyes can see. Eyes receive and process light, not cups. Your eyes are light processors, not cup processors. The “photograph” of the cup is not the cup.

Let’s make things worse! Think about light. If light bounces off of things (like your cup) and then goes into your eyes, then light has speed, right? What is that speed? Light travels at 186,282 miles per second (or about 670 million mph). It travels fast enough to circle the earth more than seven times a second. To put that speed in perspective, light coming all the way from the moon’s surface only takes 1.28 seconds to reach the Earth. That’s really fast. The moon is 238,857 miles away. A quarter-million miles in a-second-and-a-half. The implication of this is just wild.

What this means is that when you look at the moon, you are not seeing the moon as it appears right now. You are seeing the moon as it was one second ago. Merely by gazing at the moon tonight you are actually looking back in time one second.

The moon, however, doesn’t give off its own light. It merely reflects the light of the sun. So how long does it take sunlight to travel from the sun all the way to the Earth and its moon? Eight minutes. We’re talking about 93 million miles at 186,282 miles per second in about 500 seconds (or a little over eight minutes). So when you look at the sun—hopefully you don’t stare at it!—you aren’t seeing the sun as it is, but as it was eight minutes ago. You’re looking eight minutes back in time.

When you look at the planet Saturn with your naked eye—easily done if you know where and what to look for—you aren’t seeing Saturn as it is, but as it was . . . one whole hour ago.

The nearest star to our sun (our sun is a star)—Proxima Centauri (Alpha Centauri C)—is 4.3 “light years” away. A light year is the distance light travels in one year. It takes light from Proxima Centauri four years to reach us. So when you look up and see Proxima Centauri, you are not seeing Proxima Centauri as it is, but as it was four years ago.

On a clear, cold, moonless night, drive out away from the lights of “civilization” and look up using only your naked eye. The sky is a virtual canopy of stars—thousands of them. Some of the dim stars you are looking at are 2000 light years from Earth. But you are not seeing those distant stars as they are today. You are seeing them as they were 2000 years ago when Jesus of Nazareth walked the Earth. Moreover, when Jesus gazed at these distant stars, he saw them as they were 2000 years before his time, or near the time when Abraham walked the Earth.

Now there are 200 to 400 billion such stars in our Milky Way Galaxy. But, as the Hubble Space Telescope has so dramatically shown us, there are at least 100 billion galaxies out there too, each with on average 200 to 300 billion stars of their own. That brings an even more bizarre fact.

When the Hubble “looks” at a galaxy at the far edge of the known universe and provides us with an image of it, that image is not one of what the galaxy looks like now. It is an image of how it looked billions of years ago! To look at such distant galaxies is to look back in time well before the creation of telescopes, before the presence of humans on earth, before even the formation of our own solar system. How strange! The telescope orbiting Earth is viewing a time prior to the existence of Earth.

Again, things aren’t always as they seem. We can’t see anything in the heavens as it “is” right now. To stand in your backyard and look up at the stars is to leave “the now.” To stargaze is to travel backward in time. But this raises yet another oddity.

Look at your favorite coffee cup again. Not only is the cup in its cup-ness more than what your eyes can perceive, but the light traveling from your cup to your eye takes time to get there. It’s a very, very short amount of time, granted. But it takes time. Therefore, you can’t even look at your own coffee cup and see its image in “the now.” It’s nearly instantaneous, yes. And you can’t perceive it as anything other than instantaneous. But it’s not instantaneous.

When you look at your cup, you are seeing an image of it as it was a fraction of a second ago. In fact, because the speed of light is finite, there is no image that you can ever perceive visually in the actual present. Everything you perceive with your eyes is in the past due to a finite speed of light. How far in the past the object is seen depends on its distance from your eye.

Because light has a speed, you see the cup in front of you as it was fractions of a second ago. You see the moon as it was one second ago. You see the sun as it was eight minutes ago. You see Saturn as it was an hour ago. You see Proxima Centauri as it was four years ago. You see distant stars in the night sky as they were 2000 years ago.

My point? This blog is a parable of perception. When it comes to seeing, perception is not reality. But what about God? Is perception reality when it comes to God?

After much study and thought, I’m convinced that at the core of Jesus’ mission was his intent to provide for us corrective lenses. He came to reveal his heavenly Father as he really is. He came to correct our perception of God.

We tend to see the Son and the Father as different, do we not? The Father is seen as distant and judging while Jesus is seen as accessible and forgiving, even though the Jesus of the Bible insists that “when you’ve seen me, you’ve seen the Father.” (For more on this, see The Un-Religion.)

This creates a rather bizarre dilemma, doesn’t it? If you are a follower of Jesus or want to be, and if you take what he says in the Scriptures seriously, then you can trust your own perception of God, or you can trust what Jesus is telling you when it comes to seeing his Father. Is Jesus’ image of his Father direct, clear, and correct, or is yours?