The trillions of connections between nerve fibers explain the human brain's ability to think. This is especially true since the human mind can use tens of thousands of nerve fiber chains simultaneously in performing an intelligent act. Although the individual actions which occur in this 'neural net' can be visualized and understood, the multiplicity of effect cannot be. lf this process were understood, the question of how to create artificial intelligence would also be understood. Human Behavior. Newell, Shaw, and Simon are convinced that free human behavior is based on a complex but determinate set of laws. Since the human memory capacity is estimated to be at least a million billion bits of information the truth of their conviction cannot be readily proved. Many people think that human intelligence has evolved through a lengthy process of mutation and natural selection. Others think that this intelligence is based on natural neural networks alone. Whichever theory is used, natural intelligence appears to be essentially a trial and error process. The words of Donald N. Streeter serve quite well to sum human behavior: "Man is inventive and flexible. He perceives, abstracts, and associates quite well, drawing on broad experience to make decisions and check reasonableness. However, he is forgetful of detail, inaccurate, and subject to boredom and fatigue." Synthetic Intelligence Any process which can be formalized so that it can be represented as a series of instructions can, in principle, be reproduced by a computer. This idea is the basis for the artificial intelligence researcher's belief in an eventual solution. Marvin Minsky states: " … that at least some mentalist description of thought processes can be turned into specifications for the design of machines or, what is the same thing, the design of programs." Mechanics of the Digital Computer. The electronic digital computer is basically a block diagram consisting of three functions: input, process, and output. These functions are performed by various pieces of hardware: the central processing unit, the arithmetic logical unit, storage (memory), and the input-output devices (Fig. 3). The central processing unit controls all the other elements of the computer. The storage of the computer holds instructions awaiting execution. The arithmetic logical unit performs comparisons and does arithmetic. And the input-output devices receive and issue information. All of these units, working in tandem, form the physical make-up of the electronic digital computer. The actual processing within a computer is binary in nature, that is, it is controlled by the 'on or off ' condition of discrete bits of information. This is accomplished by using electronic memory devices (core, semiconductor, bubble, charge couple memory, etc.) having either an 'on' or 'off' state. Work done by a computer is controlled by its software. Software is a set of instructions for events to take place within a machine. These instructions are placed in storage where they are performed serially, that is, one at a time. Computers perform these operations in nanoseconds (10-9 sec.) Synthetic Behavior. "Research scientists in Artificial Intelligence try to get machines to exhibit behavior that we call intelligent behavior when we observe it in human beings." In Dr. James R. Slagle's words, we can see that the search for artificial intelligence is really an attempt to duplicate human behavior. Thus it is that there are three schools of thought concerned with finding the answer. The three approaches are: artificial evolution, artificial networks, and heuristic programming. Artificial evolution is an approach whereby computer simulated systems are made to evolve by mutation and selection. The main disadvantage of this approach is that it is practical only if artificial evolution can be made to proceed enormously faster than natural evolution. Artificial networks are a large number of simple elements and their interconnections. Its main advantage is that, using this approach, the system is adaptive to new situations and can learn from experience. The disadvantage is that there is little prospect of making an artificial network as large as the network in the human brain. The heuristic programming approach uses heuristics in attempts to solve problems, A heuristic is a 'rule-of-thumb' used to solve a particular problem. This technique, combined with the computer's computational power, has had a margin of success. But success is limited by the programmer's ability to conceive 'rules-of-thumb' for application to the problem. Again, Donald N. Streeter's words are most apt for summing up: "Computer Systems compared to humans are fast, accurate, and consistent in recalling and processing information, but are inflexible, requiring detailed pre-programming for all situations to be dealt with."