Trying to predict the impact of tomorrow's inventions.

• Author: Rosenberg, Nathan

WILL HAND-HELD satellite receivers, with a capacity for locating your position to within a few yards on the Earth's surface, make it impossible to get lost? Will today's paper money be rendered obsolete, not by plastic credit cards, but by the settlement of bills somewhere along the electronic superhighway?

Will international conferences in the future be conducted by participants sitting at their computer terminals, thousands of miles apart from each other? Will the mapping of the human genome lead to medical breakthroughs resulting in average life expectancies of a century or more?

Many executives, investors, and government officials hope they have answers to these questions, and they are spending billions of dollars in accordance with what they see in their crystal balls. They may want to stand back a bit, though, and keep their options open. A review of many important innovations, from the steam engine to the laser, shows an unsettling pattern--it seldom is possible to predict the full technological, economic, and social impact of inventions, even long after their commercial introduction.

Consider the laser, one of the century's most powerful advances since its invention three decades ago. Its versatility is breathtaking. Lasers are used for navigation, precision measurement, and chemical research. In surgery, detached retinas, a frequent cause of blindness, now are repaired with lasers on an outpatient basis. Lasers are gynecologists' instrument of choice in many surgical procedures. In the textile industry, they are used to cut material, speedily and accurately. Lasers are employed in millions of households for the high-quality reproduction of music recorded on compact discs.

The laser's most profound impact so far has been in telecommunications, where, with fiber optics, it is revolutionizing transmission. In 1966, the best transatlantic telephone cable could carry 138 conversations simultaneously between Europe and North America. The first fiber optic cable, installed in 1988, could carry 40,000; today's cables, nearly 1,500,000. Yet, lawyers at Bell Laboratories, which invented the laser, initially hesitated to apply for a patent, on the grounds that the laser had no possible relevance to telephones.

The experience of the laser is not unique. Guglielmo Marconi invented the radio, but thought it would be used primarily where communication by wire was impossible. (To this day, the British call the radio the wireless.") The radio in its early days was thought to be of potential use only for private communication--i.e., point-to-point communication, rather like the telephone--and not at all for communicating to a large audience of listeners. Surprising as it may seem today, the inventor of the radio did not think of it as an instrument for broadcasting. He visualized the users of his invention as steamship companies, newspapers, and navies, and these users needed directional, point-to-point communication--i.e., "narrowcasting," rather than broadcasting.

Such lack of foresight was by no means unique. According to James Martin, a communications authority, "When broadcasting was first proposed ... a man who was later to become one of the most distinguished leaders of the industry announced that it was very difficult to see...