CML 3: The Computerized Mr. Jones

Science fiction writers often try to solve the problems of old age and death by taking advantage of the idea that a human being is essentially a complex machine. In a typical scene, doctors and technicians scan the head of the dying Samuel Jones with a "cerebroscope," a highly sensitive instrument that records in full detail the synaptic connections of the neurons in his brain. A computer then systematically transforms this information into a computer program that faithfully simulates that brain's particular pattern of internal activity.

When this program is run on a suitable computer, the actual personality of Mr. Jones seems to come to life through the medium of the machine. "I've escaped death!" the computer exults through its electronic phoneme generator. Scanning about the room with stereoscopically mounted TV cameras, the computerized "Mr. Jones" appears somewhat disoriented in his new embodiment. But when interviewed by old friends, "he" displays Mr. Jones's personal traits in complete detail. In the story, Mr. Jones lives again in the form of the computer. Now his only problem is figuring out how to avoid being erased from the computer's memory.

Although this story may seem fantastic, some of the most influential thinkers in the world of modern science take very seriously the basic principles behind it. In fact, researchers in the life sciences now almost universally assume that a living being is nothing more than a highly complex machine built from molecular components. In the fields of philosophy and psychology, this assumption leads to the inevitable conclusion that the mind involves nothing more than the biophysical functioning of the brain. According to this viewpoint, we can define in entirely mechanistic terms the words we normally apply to human personality-words like consciousness, perception, meaning, purpose, and intelligence.

Along with this line of thinking have always gone idle speculations about the construction of machines that can exhibit these traits of personality. But now things have gone beyond mere speculation. The advent of modern electronic computers has given us a new field of scientific investigation dedicated to actually building such machines. This is the field of artificial-intelligence research, or "cognitive engineering," in which scientists proceed on the assumption that digital computers of sufficient speed and complexity can in fact produce all aspects of conscious personality. Thus we learn in the 1979 M.I.T. college catalog that cognitive engineering involves an approach to the subjects of mind and intelligence that is "quite different from that of philosophers and psychologists, in that the cognitive engineer tries to produce intelligence."

In this article we shall examine the question of whether it is possible for a machine to possess a conscious self that perceives itself as seer and doer. Our thesis will be that while computers may in principle generate complex sequences of behavior comparable to those produced by human beings, computers cannot possess conscious awareness without the intervention of principles of nature higher than those known to modern science. Ironically, we can base strong arguments in support of this thesis on some of the very concepts that form the foundation of artificial-intelligence research. As far as computers are concerned, the most reasonable inference we can draw from these arguments is that computers cannot be conscious. When applied to the machine of the human brain, these arguments support an alternative, non-mechanistic understanding of the conscious self.

To begin, let us raise some questions about a hypothetical computer possessing intelligence and conscious self-awareness on a human level. This computer need not duplicate the mind of a particular human being, such as our Mr. Jones, but must simply experience an awareness of thoughts, feelings, and sensory perceptions comparable to our own.

First, let us briefly examine the internal organization of our sentient computer. Since it belongs to the species of digital computers, it consists of an information storehouse, or memory, an apparatus called the central processing unit (CPU), and various devices for exchanging information with the environment.

The memory is simply a passive medium used to record large amounts of information in the form of numbers. We can visualize a typical computer memory as a series of labeled boxes, each of which can store a number. Some of these boxes normally contain numerically coded instructions specifying the computer's program of activity. Others contain data of various kinds, and still others store the intermediate steps of calculations. These numbers can be represented physically in the memory as patterns of charges on microminiature capacitors, patterns of magnetization on small magnets, or in many other ways.

The CPU performs all the computer's active operations, which consist of a fixed number of simple operations of symbol manipulation. These operations typically involve the following steps: First, from a specified location (or ''address'') in the memory, the CPU obtains a coded instruction identifying the operation to be performed. According to this instruction, the CPU may obtain additional data from the memory. Then the CPU performs the operation itself. This may involve input (reading a number into the memory from an external device) or output (transmitting a number from the memory to an external device). Or the operation may involve transforming a number according to some simple rule, or shifting a number from one memory location to another. In any case, the final step of the operation will always involve the selection of a memory address where the next coded instruction is to be sought.

A computer's activity consists of nothing more than steps of this kind, performed one after another. The instruction codes stored in the passive memory specify the operations the CPU is to execute. The function of the CPU is simply to carry them out sequentially. The CPU's physical construction, like that of the memory, may include many kinds of components, ranging from microminiature semiconductor junctions to electromechanical relays. It is only the logical arrangement of these components, and not their particular physical constitution, that determines the functioning of the CPU.