UCSB's Joseph Polchinski speaks about the search for a unified theory of the laws of physics, and the difficulty of reconciling two of the main pieces: quantum mechanics, which governs the very small, and general relativity, which governs the very large. A professor of physics and a permanent member of the Kavli Institute for Theoretical Physics, Polchinski was named UC Santa Barbara's 2014 Faculty Research Lecturer. Recorded on 12.04.2014. (#30118)