Saturday, December 15, 2007

How Imperfect the Eye

Many say that it is impossible for the eye could have evolved, because it's too complex and too perfect and elegant. Evolution could never do that (thousands of monkeys on typewriters couldn't write King Lear). Thus, some author, God, must have created it.

But, the eye isn't perfect. Not by a long shot. In A Fin is a Limb is a Wing, in the November 2006 National Geographic, Carl Zimmer points out the comic flaws. The light gathering cells point inward, not outward toward the light. And the optic nerve is in front of the retina -- getting in the way of seeing -- and right in the center of the eye, the nerve plunges through a hole to the brain. Creating the blind spot.

Which is why if you want to clearly see a star, you have to look to the side of it, not at it.