Monday, September 6, 2010

What Is Consciousness?

by Richard Crews
Consciousness is a problem-solving strategy, the result of a long, complex, and arduous evolution of a most curious chemical compound, deoxyribonucleic acid (DNA).

DNA first happened on the scene about three and a half billion years ago. Exactly how this came about is not entirely clear. A few billion years after the Big Bang (which occurred 13.7 billion years ago), supernovae burst forth all over the Universe. They came from stars that had accumulated so much hydrogen--gradually accreting it under its own gravitational weight--that they had grown hot and pressured beyond nuclear synthesis of helium and other small elements. They had grown so fiery bright and massive that they exploded. In doing so they spewed forth into the cosmos an array of medium-small chemical elements they had synthesized in their pressure-cooker phase--elements such as carbon, nitrogen, and oxygen--elements necessary for life. This enriched cosmic dust raced outward from its exploding star. But gradually, because of its own gravity, it began to coagulate into gaseous clouds; these clouds were pulled into rings around other stars, and ultimately they coagulated into planets.

These planets--such as the early Earth--were hellish places, full of molten rock, volcanoes, and violent lightening storms. But gradually they cooled--more and more, here and there--and the rich chemical soup they had inherited from supernovae billions of years before was churned and frothed a million, million different ways. Out of this came--among many, many failed attempts--the first primitive building blocks of life: ultimately, DNA.

DNA has one unique and curious characteristic: given the right chemical froth, it makes more of itself. There is no other (known) chemical compound among the vast array of compounds the Universe plays with that has this characteristic. But DNA is a complex and delicate chemical structure and so, like any chemical (even ones with far simpler and hardier chemical bonds) it is subject to degradation. It can fall prey--and its unique characteristic, self-duplication, can be lost--due to heat, acids or other harsh chemicals, or even bombardment by electromagnetic radiation such as X-rays or by cosmic rays.

Imagine, then, that primitive forms of DNA brewing on Earth in its fertile stew were occasionally struck by cosmic rays coming from outer space. Usually nothing happened--the cosmic rays were too weak or not aimed precisely right; the chemical bonds of the DNA were strong enough to withstand them. Often, on the other hand, if the rays were strong enough to have an effect their effect was catastrophic--the DNA was destroyed. But on rare occasions the cosmic rays caused subtle damage; the DNA continued to be able to function, but in some altered way. It had been mutated.

Most of the mutations--rare as they were--were disruptive. They caused the DNA to function poorly and to die off. But ever more rarely--much rarer than rare--a mutation would occur that improved the DNA's functions, for example, one that enabled the DNA more easily to find and bind the chemical constituents it needed to perform its magic self-replication process.

Imagine now this salutary mutation process, though it occurred rarely, happening--over a billion years and more--millions and millions of times. Gradually the DNA became more and more complex, and better and better at reduplicating itself. Gradually it "learned" to join forces with other, slightly different DNA molecules for mutual advantage. Gradually it formed colonies, organisms, and then more and more complex organisms; gradually it became better and better at replicating itself--and at performing the other functions that supported that self-replication process: finding the necessary raw materials (food) including moving around and searching the environment; getting rid of useless byproducts (excretions); protecting itself from disruptive influences; and making more, faster, better copies of itself (procreation).

But how does this advanced, complex DNA organism make the myriad decisions necessary to survive and thrive? It does so by developing a way of evaluating the choices it must make and comparing their hypothetical outcomes. In other words, it does so by sorting through the incoming sensory data, comparing them with remembered experiences, imagining itself dealing with the data this way and that--and choosing the optimal behavior that is most likely to produce the desired outcome. In other words, it develops a network of neurons--a brain--and a way of imagining itself in a series of behavioral scenarios. In other words, it develops a reproducible and more or less consistent image of itself. In other words, it becomes conscious.

What Is Consciousness? Consciousness is a problem-solving strategy, the result of a long, complex, and arduous evolution of a most curious chemical compound, deoxyribonucleic acid (DNA).