AI for Game Developers

Chapter 10. Fuzzy Logic

In 1965 Lotfi Zadeh, a professor at the University of California Berkeley, wrote his original paper laying out fuzzy set theory. We find no better way of explaining what fuzzy logic is than by quoting the father of fuzzy logic himself. In a 1994 interview of Zadeh conducted by Jack Woehr of Dr. Dobbs Journal, Woehr paraphrases Zadeh when he says “fuzzy logic is a means of presenting problems to computers in a way akin to the way humans solve them.” Zadeh later goes on to say that “the essence of fuzzy logic is that everything is a matter of degree.” We’ll now elaborate on these two fundamental principles of fuzzy logic.

What does the statement “problems are presented to computers in a way similar to how humans solve them” really mean? The idea here is that humans very often analyze situations, or solve problems, in a rather imprecise manner. We might not have all the facts, the facts might be uncertain, or perhaps we can only generalize the facts without the benefit of precise data or measurements.

For example, say you’re playing a friendly game of basketball with your buddies. When sizing up an opponent on the court to decide whether you or someone else should guard him, you might base your decision on the opponent’s height and dexterity. You might decide the opponent is tall and quick, and therefore, you’d be better off guarding someone else. Or perhaps you’d say he is very tall but somewhat slow, so you might do fine against him. You normally wouldn’t say ...