Niles Eldredge is an emeritus curator in the Division of Paleontology at the American Museum of Natural History and one of the founders of the hierarchy theory of evolution. He is the author, most recently, of Eternal Ephemera: Adaptation and the Origin of Species from the Nineteenth Century through Punctuated Equilibria and Beyond. Telmo Pievani is professor in the Department of Biology at the University of Padua, where he holds the first Italian chair of the philosophy of biological science. Emanuele Serrelli is a fellow at the University of Milano-Bicocca and a researcher in the philosophy of science who collaborates with several universities around the world. Ilya Tëmkin is associate professor of biology at Northern Virginia Community College and a research associate at the National Museum of Natural History, Smithsonian Institution. All four are members of the Hierarchy Group.