Logic, Rational Agency, and Intelligent Interaction Johan van Benthem Abstract: This was an invited lecture at the 13th Congress for Logic, Methodology, and Philosophy of Science, Beijing, August 2007. We claim that observation, inference, and communication are usually interwined in rational agency, and accordingly, that logical systems should, and can explain these informational processes explicitly in their proper entanglement. We show how this works with current dynamic epistemic logics for information update, belief revision, and preference change, and we make the link to strategic behaviour and game theory. Finally, we discuss the changing view of logic which emerges out of this stance, and its philosophical repercussions. The paper will appear in the DLMPS Proceedings, College Publications, London, edited by Dag Westerståhl et al.