THE DEFINITION OF A MECHANICAL BRAIN
Now when we speak of a machine that thinks, or a mechanical brain, what do we mean? Essentially, a mechanical brain is a machine that handles information, transfers information automatically from one part of the machine to another, and has a flexible control over the sequence of its operations. No human being is needed around such a machine to pick up a physical piece of information produced in one part of the machine, personally move it to another part of the machine, and there put it in again. Nor is any human being needed to give the machine instructions from minute to minute. Instead, we can write out the whole program to solve a problem, translate the program into machine language, and put the program into the machine. Then we press the “start” button; the machine starts whirring; and it prints out the answers as it obtains them. Machines that handle information have existed for more than 2000 years. These two properties are new, however, and make a deep break with the past.
How should we imagine a mechanical brain? One way to think of a mechanical brain is shown in [Fig. 2]. We see here a railroad line with four stations, marked input, storage, computer, and output. These stations are joined by little gates or switches to the main railroad line. We can imagine that numbers and other information move along this railroad line, loaded in freight cars. Input and output are stations where numbers or other information go in and come out, respectively. Storage is a station where there are many platforms and where information can be stored. The computer is a special station somewhat like a factory; when two numbers are loaded on platforms 1 and 2 of this station and an order is loaded on platform 3, then another number is produced on platform 4.
Fig. 2. Scheme of a mechanical brain.
We see also a tower, marked control. This tower runs a telegraph line to each of its little watchmen standing by the gates. The tower tells them when to open and when to shut which gates.
Now we can see that, just as soon as the right gates are shut, freight cars of information can move between stations. Actually the freight cars move at the speed of electric current, thousands of miles a second. So, by closing the right gates each fraction of a second, we can flash numbers and information through the system and perform operations of reasoning. Thus we obtain a mechanical brain.
In general, a mechanical brain is made up of:
1. A quantity of registers where information (numbers and instructions) can be stored.
2. Channels along which information can be sent.
3. Mechanisms that can carry out arithmetical and logical operations.
4. A control, which guides the machine to perform a sequence of operations.
5. Input and output devices, whereby information can go into the machine and come out of it.
6. Motors or electricity, which provide energy.
THE KINDS OF THINKING A
MECHANICAL BRAIN CAN DO
There are many kinds of thinking that mechanical brains can do. Among other things, they can:
- 1. Learn what you tell them.
- 2. Apply the instructions when needed.
- 3. Read and remember numbers.
- 4. Add, subtract, multiply, divide, and round off.
- 5. Look up numbers in tables.
- 6. Look at a result, and make a choice.
- 7. Do long chains of these operations one after another.
- 8. Write out an answer.
- 9. Make sure the answer is right.
- 10. Know that one problem is finished, and turn to another.
- 11. Determine most of their own instructions.
- 12. Work unattended.
They do these things much better than you or I. They are fast. The mechanical brain built at the Moore School of Electrical Engineering at the University of Pennsylvania does 5000 additions a second. They are reliable. Even with hundreds of thousands of parts, the existing giant brains have worked successfully. They have remarkably few mechanical troubles; in fact, for one of the giant brains, a mechanical failure is of the order of once a month. They are powerful. The big machine at Harvard can remember 72 numbers each of 23 digits at one time and can do 3 operations with these numbers every second. The mechanical brains that have been finished are able to solve problems that have baffled men for many, many years, and they think in ways never open to men before. Mechanical brains have removed the limits on complexity of routine: the machine can carry out a complicated routine as easily as a simple one. Already, processes for solving problems are being worked out so that the mechanical brain will itself determine more than 99 per cent of all the routine orders that it is to carry out.
But, you may ask, can they do any kind of thinking? The answer is no. No mechanical brain so far built can:
- 1. Do intuitive thinking.
- 2. Make bright guesses, and leap to conclusions.
- 3. Determine all its own instructions.
- 4. Perceive complex situations outside itself and interpret them.
A clever wild animal, for example, a fox, can do all these things; a mechanical brain, not yet. There is, however, good reason to believe that most, if not all, of these operations will in the future be performed not only by animals but also by machines. Men have only just begun to construct mechanical brains. All those finished are children; they have all been born since 1940. Soon there will be much more remarkable giant brains.