Part 1: Chapter 1
The problem of speed
So far, this chapter has presented the abstract concept of a space that can contain any kind of information or object. The objects or information in this space are located where the parameters describing the object or information intersect.
As has been noted, this is somewhat similar to the way the Google search engine stores and locates information sources, where the parameters that define the location in this space are keywords or phrases. Moving around a Google information space is achieved by selecting different combinations of keywords and phrases.
Google adds other parameters to this space in the form of functions and added information (i.e., the popularity of the source and its links to others popular sources of information), which allows information to be ordered when more than one source of information appears at the location of selected keywords or phrases.
Depicting the functioning of the human brain in a similar abstract way, would see the brain containing a variety of information and knowledge that is stored away in some kind of memory system. Like Google, the stored information can be accessed by energizing appropriate parameters.
The parameters triggering areas of memory can, like Google, take the form of key words and phrases. But, the parameters can also take the form of touch, sounds, visual images or smells. In general, accessing any part of the human memory is initiated by means of a combination, or pattern, of sensory inputs.
As an abstraction, this is patently obvious, but, if consideration is given to the mechanisms that enable memories to be stored and sensory inputs to point to discreet areas of memory, a formidable problem is revealed.
There are billions of sensory cells in the human body. They are continuously sending signals to the brain. If these are seen as the parameters describing the possible contents of memory, it will be realized that a highly efficient filtering and selection system has to be in place to enable exact memory locations to be energized in response to this gargantuan torrent of information continuously arriving at the brain.
The inadequacy of information technology concepts to cope with this problem is highlighted by a few relevant facts. Firstly, the brain consists of something of the order of fifty billion neurons. Secondly, the processing speeds of neurons are much slower than the speeds of the elements that make up computer processors.
The exact nature of the problem is highlighted by considering the human visual system. The visual information that is impinging upon the retinas of our eyes from the external world is incalculable. The retinas are capable of sensing something like ten billion bits of this information a second. The capacity of the optic nerve will allow only about three million bits of information per second of this information to be transmitted to the brain. The brain can scrutinize this information at the rate of only one thousand bits per second and long term memory storage is limited to one to ten bits per second. These are the practical realities that have to be considered when trying to explain how sensory inputs are routed to trigger appropriate neural responses in the brain.
In terms of conventional information technology it would seem impossible for the brain to provide the split second performance that we know it is capable of. How does Nature do it? We can assume that the brain processes and modifies all sensory inputs using a myriad of neural networks, but there is still the problem of addressing and coordinating these networks. Any explanation in terms of conventional computer technology would fail to provide answers that can account for the rapid speed.