Blog post with show notes and transcript: https://www.preposterousuniverse.com/podcast/2018/10/15/episode-18-clifford-johnson-on-whats-so-great-about-superstring-theory/ Patreon: https://www.patreon.com/seanmcarroll String theory is a speculative and highly technical proposal for uniting the known forces of nature, including gravity, under a single quantum-mechanical framework. This doesn't seem like a recipe for creating a lightning rod of controversy, but somehow string theory has become just that. To get to the bottom of why anyone (indeed, a substantial majority of experts in the field) would think that replacing particles with little loops of string was a promising way forward for theoretical physics, I spoke with expert string theorist Clifford Johnson. We talk about the road string theory has taken from a tentative proposal dealing with the strong interactions, through a number of revolutions, to the point it's at today. Also, where all those extra dimensions might have gone. At the end we touch on Clifford's latest project, a graphic novel that he wrote and illustrated about how science is done. Clifford Johnson is a Professor of Physics at the University of Southern California. He received his Ph.D. in mathematics and physics from the University of Southampton. His research area is theoretical physics, focusing on string theory and quantum field theory. He was awarded the Maxwell Medal from the Institute of Physics. Johnson is the author of the technical monograph D-Branes, as well as the graphic novel The Dialogues.