Sunday, June 27, 2010

The Brain: A Special-Purpose Computer

by Richard Crews
You would not expect the computer at an ATM--quick and versatile as it is--to fly a jet; nor a hospital lab analyzer to scan sales at a super market. They are special-purpose computers, able at what they do but woefully lacking at the versatility to step out of their assigned tasks.

Similarly, the human brain evolved under certain circumstances to handle certain problems--to seek and assess food, to watch for and avoid predators, to court and procreate, and to raise children, and so forth. Is it any wonder that when we ask it to step outside of those circumstances, it balks and falters and cannot do the job?

For example, the brain evolved for problems in a "mid-size" range--to assess the progress of predator or prey running through the woods; to throw, catch, or dodge a projectile under the influence of gravity and momentum; to run or climb and avoid falling. When we tell it that at the astronomical-size range, two photons may be fired in opposite directions, each at the speed of light, yet they are still traveling at the speed of light with respect to one another, the mind stalls. Similarly when we try to imagine a two dimensional surface, somehow we can only see it as if it were suspended in a three-dimensional world. Or four spacial dimensions (time doesn't count in this exercise)--the mind balks--much less five, six, or more dimensions. And though sound and patterns of light come easily to our ways of thinking, we have no framework for envisioning the thousands and thousands of radio waves with their complicated and separable messages that we know are coursing through our bodies at every second of the day and night.

At the sub-microscopic level, particles leap across impenetrable barriers by ceasing to exist on one side and taking up their existence on the other. Some processes do not occur until they are observed; others cannot occur while they are observed. Such things simply do not happen at the perceptual level our brains developed to handle; we simply cannot grok them.

Finally, consider problems of causation. It is very useful in daily life to project effects--to imagine jumping from a high place or trying to lift a tree and to imagine the results without actually "doing" it. And to infer causes--there is a noise; there must be something there that caused it. My hand hurts and is bleeding--something must have caused that. So it is natural for us to try to find reasons and causes for any mysterious things we sense or imagine around us--for the origin and evolution of life, for example, or the origin of the universe.