Translating telephones that convert speech from one language to another (by first recognizing speech in the original language, translating the text into the target language, then synthesizing speech in the target language) will be demonstrated by the end of this century and will become common during the first decade of the twenty-first century. Conversation with computers that are increasingly unseen and embedded in our environment will become routine ways to accomplish a broad variety of tasks.

In a classic paper published in 1950, Alan Turing foretold that by early in the next century society would take for granted the pervasive intervention of intelligent machines. This remarkable prediction -- given the state of hardware technology at that time -- attests to his implicit appreciation of Moore's law.


Building HAL's Language Knowledge Base

For reasons that should be clear from our discussion, creating a machine with HAL's ability to understand spoken language requires a level of intelligence and mastery of knowledge that spans the full range of human cognition. When we test our own ability to understand spoken words out of context (i.e., spoken in a random, nonsense order), we find that the accuracy of speech recognition diminishes dramatically, compared to our understanding of words spoken in a meaningful order. Once, as an experiment, I walked into a colleague's office and said "Pod 3BA." My colleague's response was "What?" When I asked him to repeat what I had said, he couldn't. HAL, of course, has little difficulty understanding this phrase when Dave asks him to prepare Pod 3BA; it makes sense in the context of that conversation, and we human viewers of the movie easily understood it too.

Understanding spoken language uses the full range of our intelligence and knowledge. Many observers (including some authors of chapters in this book) predict that machines will never achieve certain human capabilities -- including the deep understanding of language HAL appears to possess. If by the word never, they mean not in the next couple of decades, then such predictions might be reasonable. If the word carries its usual meaning, such predictions are shortsighted in my view, reminiscent of predictions that "man" would never fly or that machines would never beat the human world chess champion.

With regard to Moore's law, the doubling of semiconductor density means that we can put twice as many processors (or, alternatively, a processor with twice the computing power) on a chip (or comparable device) every eighteen months. Combined with the doubling of speed from shorter signaling distances, such increases may actually quadruple the power of computation every eighteen months (that is, double it every nine months). This is particularly true for algorithms that can benefit from parallel processing. Most researchers anticipate the next one or two turns of Moore's screw; others look ahead to the next four or five turns. But Moore's law is inexorable. Taking into account both density and speed, we are presently increasing the power of computation (for the same unit cost) by a factor of sixteen thousand every ten years, or 250 million every twenty years.