Is Seeing Believing? Direct and Indirect Observation in Physics

Allan Franklin, University of Colorado

Tuesday, September 19, 2017 - 5:30pm

American Institute of Physics (College Park, MD)

American Center for Physics
1 Physics Elipse
College Park, MD 20740
In their recent paper announcing the observation of gravity waves the LIGO collaboration stated, “This is the first direct detection of gravitational waves…”. This was to distinguish their result from those of Taylor, Hulse, and Weisberg and Taylor in which the decrease in the period of a binary pulsar was used to “… establish, with a high degree of confidence the existence of gravitational radiation as predicted by general relativity.” The implication by LIGO was that the latter results were not a direct observation.
This raises several interesting questions. One might ask how one can distinguish between direct and indirect observation and whether that distinction is exemplified in the practice of science. One might also ask whether a direct observation has more epistemic weight than an indirect observation? In this talk I will briefly discuss several episodes from the history of modern physics in an attempt to answer those questions. These episodes will include the discovery of the neutrino, of the positron, and of the Higgs boson.
Allan Franklin has been a professor of physics at the University of Colorado since 1967. Franklin began his career as an experimental high-energy physicist. In the mid 1970s he changed his research interests to the history and philosophy of science, focusing particularly on the roles of experiment in physics. He has published eleven books on both the history and philosophy of science and physics, including The Neglect of Experiment (1986), Experiment, Right or Wrong (1990), Can That be Right? Essays on Experiment, Evidence and Science (1999), Are There Really Neutrinos? An Evidential History (2000), and Selectivity and Discord: Two Problems of Experiment (2002). In 2016 he was awarded the Pais Prize for History of Physics by the American Physical Society.