This talk is about a direction in logic which attempts to have something to say, and something to learn, from computational linguistics and natural language processing.

Much of modern logic originates in work on the foundations of mathematics. My talk reports on work in logic that has a different goal, the study of interference in language. This study leads to what I will call “natural logic,” the enterprise of studying logical interference in languages that look more like natural language than standard logical systems.

By now there is a growing body of work which presents logical systems that differ from first-order logic in various ways. Most of the systems are complete and decidable. Some are modern versions of syllogistic logic, but with additional features not present in syllogistic logics. And then there are flavors of logic which look rather far from ethical traditional or modern logic.

The talk will be programmatic and far-ranging rather than detailed. I hope to touch on computer implementations of natural logics, teaching materials on this topic, and interactions of logic and cognitive science.