Wednesday, July 09, 2003

The Sudden Arrival of Vision: Three Stories

One. For the first 300,000 years of the universe's existence, the electron density was so high that photons could not freely travel. Once the density was sufficiently low, photons were "freed" from the primordial mass and it became possible to see. Of course, there was no one around at the time to see, but when we look out in the universe and thus into the past, that line is the barrier beyond which there is only a glowing cloud, impermeable to vision.

Two. One of the great mysteries of child development is what's called "infantile amnesia," which is the phenomenon we all share that we cannot remember anything before a certain age. There's no generally accepted explanation to this, but there are hints in the fact that infants earlier than this age do have both short-term and long-term memory. It's not that they are insufficiently developed to store any memory, it's just that, for some reason, the memories are not accessible or perceived at a later age in the same conscious way that normal autobiographical memory is. But to me it is a similar story to the universe: a sudden clearing, a sudden tipping point where the connectivity of neurons, or photons, is causally distant enough that what was a soft glowing cloud is suddenly clear.

Three. About 540 million years ago, the sophistication and variety of forms of living creatures increased dramatically. This increase is known as the Cambrian Explosion, and was best popularized by Steven Jay "Spandrel" Gould in his book Wonderful Life. But why did this explosion happen? Self-organization proponents like Stuart Kauffman might not be surprised, but Oxford biologist Andrew Parker has an intriguing explanation in his book In the Blink of an Eye: it was the evolution of vision. Once you have vision, you can hunt, you can tell relatives from predators (if in fact they are different), and you can evolve a whole host of new features like color that will matter to the environment.

So. We see that the conditions for vision can suddenly crystalize in an environment; that existing but invisible processes suddenly change their form and our perceptions of them; and that vision changes the competitive landscape so enormously that the basic patterns of life transform.

What vision is about to precipitate into the world today?