Intelligence in Nature - Jeremy Narby [50]
True, humans are starting to design technologies that emulate the ways of nature. But so far, among all the devices made of metal alloys, silicone, plastic, and rubber, there is nothing really equivalent to living beings made of living cells. Each individual cell in a body is alive. Living cells are themselves creatures with a life cycle, and they must look after their own survival by adapting to the circumstances they encounter. This vital aspect of all biological creatures is absent in machines such as computers, the elementary particles of which are inert materials. Computers may now greatly exceed the computational capacities of humans. And they may now be endowed with âartificial intelligence,â meaning to say that they can be programmed to do things that would otherwise require intelligence if done by a living organism. But this does not mean that machines are alive in the biological sense. It means that they can be made to exhibit certain characteristics usually associated with life.
Some computer programs can generate informational entities that reproduce, evolve, and mutate, all the while competing with one another. These forms of âartificial lifeâ function in ways comparable to living organisms. But computer programs written with sequences of ones and zeros (representing voltage on and off) cannot move around and feed themselves in the material world, and are not equivalent to living beings like bacteria, birds, and humans.
I do not know if machines know, but my impression is that I do. How does knowledge come to me? My knowing self seems to me to be lodged inside my head, behind the eyes, slightly above nostril level. And contemporary science confirms that a large part of human knowledge, including experience, sensation, and thought, is mediated by our brains.
The human brain has the consistency of jelly. According to some estimates, it contains about one hundred billion nerve cells, or neurons. Each neuron can form thousands of links with other neurons. This means that the human brain has many times more connections than stars in our galaxy. How such a complex network takes shape in an organism that originates as a single cell defies current understanding.
Scientists estimate that a cubic millimeter of the brainâs cortexâa sphere small enough to fit inside this oâcontains over two miles of connecting neural âwireâ (or the extensions of neurons known as axons). I tried forming an image of this in my mind but failed repeatedly. I found this difficulty was compounded by knowing that I was using my own brain to consider the matter. Conducting an inquiry with the very object of inquiry can be tricky. The human brain can have difficulty thinking about itself.
When I look at the world around me, I see three-dimensional, color images accompanied by sensations of sound, taste, smell, and touch. These images look like they are outside my head, but they are actually a reconstruction operated by my brain. How do pictures emerge from the gelatinous matter which is my brain? How do images form inside pinkish gray jelly? The mystery is not new, and remains unsolved.
Since the 1990s, scientists have generated vast amounts of new information about the brain and mind thanks to innovations in brain-imaging techniques. Using functional magnetic resonance imaging (MRI), scientists can now peer inside the thinking, feeling brain, and see it in action. Magnetic scans work by revealing increased oxygen-rich blood flow, which occurs when a particular location of the brain is engaged in a specific task. A researcher need only put a few people into the scanner and ask them to think of an idea or behave in a given way. After subtracting the brain areas that are active in performing basic tasks, the machine depicts the brain areas critical to the task at hand as splotches of light on a screen. The neurons involved in identifying the color red, or recognizing a face, or adding a sum, or categorizing apples as fruits, light up on the screen like magic. Such research has led to a clearer understanding of the brainâs spatial organization.