Recognizing intentional signals and their meaning in non-human communication

How can we tell if someone is trying to talk to us—especially when that someone is not a member of our species (or even from our solar system)? And once we have detected a signal, how can we tell what it means? This chapter outlines an approach based on the work of the twentieth-century philosopher Paul Grice. It begins by developing two key ideas from Grice: (i) the idea that communication is a cooperative endeavor, and (ii) the idea that meaning (in one interesting sense) is a matter of acting with particular intentions. It then shows how these two ideas have been developed into a toolkit that has proved very fruitful in studying non-human animal communication. Applying this toolkit to extraterrestrial signals would be challenging, but the chapter concludes by suggesting strategies with which to begin.