When most people think of artificial intelligence (AI) they think of HAL 9000 from “2001: A Space Odyssey,” Data from “Star Trek,” or more recently, the android Ava from “Ex Machina.” But to a computer scientist that isn’t what AI necessarily is, and the question “what is AI?” can be a complicated one.
One of the standard textbooks in the field, by University of California computer scientists Stuart Russell and Google’s director of research, Peter Norvig, puts artificial intelligence in to four broad categories:
The differences between them can be subtle, notes Ernest Davis, a professor of computer science at New York University. AlphaGo, the computer program that beat a world champion at Go, acts rationally when it plays the game (it plays to win). But it doesn’t necessarily think the way a human being does, though it engages in some of the same pattern-recognition tasks. Similarly, a machine that acts like a human doesn’t necessarily bear much resemblance to people in the way it processes information.
The issue is that much of “common sense” is very hard to model. Computer scientists have taken several approaches to get around that problem. IBM’s Watson, for instance, was able to do so well on Jeopardy! because it had a huge database of knowledge to work with and a few rules to string words together to make questions and answers. Watson, though, would have a difficult time with a simple open-ended conversation.
Beyond tasks, though, is the issue of learning. Machines can learn, said Kathleen McKeown, a professor of computer science at Columbia University. “Machine learning is a kind of AI,” she said.
Some machine learning works in a way similar to the way people do it, she noted. Google Translate, for example, uses a large corpus of text in a given language to translate to another language, a statistical process that doesn’t involve looking for the “meaning” of words. Humans, she said, do something similar, in that we learn languages by seeing lots of examples.
That said, Google Translate doesn’t always get it right, precisely because it doesn’t seek meaning and can sometimes be fooled by synonyms or differing connotations.