Saturday, October 29, 2011

Limitations of the Human Brain

by Richard Crews
The human brain evolved over the past couple of million years mainly to help our ancestors evade predators and find food and shelter (and, of course, sex mates). The brain's main function and the reason it got so complicated--so good at making certain kinds of observations, storing certain kinds of memories, puzzling out and solving certain kinds of problems--was that doing those particular things well provided a very powerful evolutionary advantage. Human beings have never been the strongest, fastest, or most durable species on the block, but we became the smartest at solving certain kinds of problems.

These are important problems, problems that are key to survival, but they are CERTAIN problems, not just any and all kinds of problems.

As to evolving adaptations to more modern ways, remember that our ancestors have only been herding and farming for a few thousand years--barely a drop in the evolutionary bucket (10,000 years is 1/2 of 1% of 2 million years). Even more recently, our fascination with and "belief" in mathematics and science only goes back a few hundred years (Archimedes, sometimes called the father of mathematics and science, lived less than 2,500 years ago).

It is interesting to realize that all the problems our brains grew up solving involve processing data in a sort of middle range--not too big and not too small, not too fast and not too slow. Our ancestors never had to worry about anything smaller than a grain of sand or larger than a mountain--or events on a time scale smaller than the blink of an eye or greater than a few years. When science and mathematics came along, they developed theories and equations to understand and explain observations in this middle time-space range. Since our brains had been working out problems in this time-space range for a couple of million years, it all made good sense. The science and mathematics developed by Isaac Newton was elegant and clear; in fact, in retrospect it all seemed obvious.

Then over the past one hundred years scientists have noticed that outside of this comfortable, middle time-space range things can get pretty weird. Sometimes things just don't follow Newtonian rules. Atomic-size particles can sometimes be in more than one place at the same time; sometimes they can jump from place to place without passing through the intervening space; sometimes they can communicate with or affect one another instantly even though they are millions and millions of miles apart; perhaps worst of all, sometimes they are created out of nothing and disappear into nothing. The very tiny world of quantum physics seems to have its own rules, very different from the ones our brains grew up dealing with.

There are also weirdnesses on the "up" side, the world of the very large or very fast. If a beam of light is traveling away from you in one direction and another beam is going away from you in the opposite direction, you can't just add their speeds together to find out how fast they are going away from each other. In fact, they are also going away from each other at the same speed that they are each going away from you (the speed of light). Weird. And what about time? Exactly what time it is and how fast time is plodding along depends on how fast you are going; the faster you travel, the more time slows down. This is Einstein's world of "relativity."

The reason that the quantum world and the relativity world seem weird to us is that our brains did not have to deal with them when we were evolving. Our brain computers developed capacities for understanding the world at the Newtonian level, but not at the quantum or relativity levels.

There is another realm our brains simply cannot handle, a realm suggested by the questions, "Where did it all come from?" "Why is there something rather than nothing?" and "What does 'God' mean?" The processes that our brains evolved in solving Newtonian-level problems lead us to stumble upon those questions, but they are not "real" or "answerable" questions in the sense that our brains are not equipped to handle them.

One does not attempt to write a letter on a banana, travel a thousand miles via a wheelchair, or access the Internet using only a pencil. Those are wonderful objects, but they were not designed with those problems in mind and cannot handle them. Similarly, there is no point in trying to get the human brain to "understand" problems or "answer" questions that it was not designed to handle. We can design tools like the microscope and the telescope to translate some very small or very large observations into our middle time-space range. (The "tools" we develop can also be concepts and equations.) But translations are always inaccurate and incomplete. They distort the source to fit our given concepts and perceptual capacities.

Similarly, our languages grew up to fit the middle time-space range. Not everything that is linguistically allowable is true or possible. Yogi Berra became famous for saying things like, "A great batter will beat a great pitcher every time, and vice versa" and "When you come to a fork in the road, take it." Statements like these are funny because they are linguistically allowable--in other words, at first blush they make sense--but on closer consideration, they are ridiculous. Noam Chomsky formed the sentence, "Colorless green ideas sleep furiously" to illustrate that our brains allow grammatical constructions that are clearly meaningless.

The human brain is a marvelous device. It serves us well, but only within the realms it was designed to handle. When we ask it to extend its services beyond those realms, we must do so very carefully. Otherwise we can delude ourselves; in fact, things can get pretty ridiculous.