Can a scientific theory ever be confirmed? Must a scientific theory be falsifiable? These are deep questions that have fascinated philosophers from David Hume to Karl Popper, and continue to be at the core of scientific reasoning. Theories such as that of the multiverse or almost all string theories make no empirically verifiable predictions. Does this move them into the realm of metaphysics, or even quasiscience? Modern philosophers of science have moved on beyond the notion of falsifiability. They refer to the old school who believed in empirical testing of scientific theories as the Popperazzi. Now one applies statistical inference, pioneered by Reverend Thomas Bayes in the 19th century, to infer the likelihood that a theory is correct. Philosophers argue that while one can never prove that a theory of the universe is correct, one can increase the level confidence in the theory even without any empirical tests, if the theory satisfies certain conditions that I will explain. In this way one can provide non-empirical support for string theory and even the theory of the multiverse.
No reservations are required for this lecture. It will be run on a ‘first come, first served’ basis. Doors will open 30 minutes before the start of the lecture.
Gresham Professor of Astronomy, Joseph Silk FRS, is a research scientist at the Service d’Astrophysique, CEA, Saclay and the Institut d’Astrophysique, Université Pierre et Marie Curie, Paris, Homewood Professor in the Department of Physics and Astronomy, Johns Hopkins University, Baltimore, and Senior Fellow in the Beecroft Institute for Particle Astrophysics and Cosmology at the Department of Physics, University of Oxford. He is a leading expert on the early Universe, a Balzan Prize winner and one of the world’s most sought-after science communicators.
A graduate of the Universities of Cambridge and Harvard, Professor Silk was a postdoctoral fellow at Cambridge and Princeton before joining the University of California, Berkeley, where he remained for the next three decades, eventually as Professor of Astronomy and Physics. He was Savilian Chair of Astronomy at the University of Oxford from 1999 to September 2011. He started his current positions of Professor of Physics and Astronomy with the Johns Hopkins University in 2010, and Professor of Physics at the Institut d’Astrophysique at UPMC in 2011.
Professor Silk is one of the world’s leading experts in theoretical cosmology, dark matter, galaxy formation and cosmic microwave background. He conducted important early work on homogeneities in the cosmic microwave background and how they are influenced by density fluctuations in the matter of the early universe, in particular by a damping effect that has become known as “Silk damping”. He has also made pioneering advances in understanding the nature of dark matter, and explored novel indirect methods for its detection which have inspired large-scale experiments with newly-developed telescopes. Professor Silk’s studies of galaxy formation and his work on the dynamics of mass loss and the feedback mechanisms from star formation and evolution formed a highly significant basis for subsequent work in this important field. In 2011 he won the Balzan Prize for this pioneering work on the infant universe.
Having delivered some of the most important invited astronomy lectures around the globe and with over 500 publications to his name, Professor Silk is one of the world’s foremost science communicators. His books include: The Big Bang, Horizons of Cosmology, The Infinite Cosmos, On the Shores of the Unknown, A Short History of the Universe and Cosmic Enigmas.
Appointed Gresham Professor of Astronomy in 2015, Professor Silk will deliver series of lectures, entitled The Biggest Questions in the Universe, on aspects of astronomy and cosmology which he believes will offer new insights into contemporary investigations into the nature of the Universe, its formation and phenomenon.