\small is it possible for two intelligent players to communicate meaningfully with each other, without any prior common background? what does it even mean for the two players to understand each other? in addition to being an intriguing question in its own right, we argue that this question also goes to the heart of modern communication infrastructures, where misunderstandings (mismatches in protocols) between communicating players are a major source of errors. we believe that questions like this need to be answered to set the foundations for a robust theory of (meaningful) communication.\\ in this talk, i will describe what computational complexity has to say about such interactions. most of the talk will focus on how some of the nebulous notions, such as intelligence and understanding, should be defined in concrete settings. we assert that in order to communicate "successfully," the communicating players should be explicit about their goals - what the communication should achieve. we show examples that illustrate that when goals are explicit the communicating players can achieve meaningful communication.\\ based on joint works with oded goldreich (weizmann) and brendan juba (mit). \\ lunch will be served following the seminar. your rsvp must be received by mon., feb. 22nd (for catering purposes), aallen@ece.ucsd.edu