Some recent developments in the computer industry make scientists predict that the gap between human beings and machines will be closed about the year 20000.

　　To understand the significance of this prediction let us compare the human brain with existing computers. The brain consumes electrical energy at the rate of 25 watts and occupies a volume of one tenth of a cubic foot. The brain houses between 10 billion and 100 billion items of information. Every brain cell is directly connected to many other cells. As a result, the cells in which information is stored can communicate with thousands of other cells.

　　However, the computer consumes 1000,000 watts of electrical power and occupies hundreds of cubic feet of space. Its million items of immediately accessible information. In contrast, the computer memory is like a cell of pigeonholes, with no thinking capacity and no connections elsewhere.

　　In a word, the electronic brains are hopelessly inadequate in comparison with the human brains.