Perhaps no scientific theory has been more rigorously and precisely validated than quantum mechanics. Its mathematical grounding has proven extremely powerful: lasers, semiconductors, and MRIs are just a few of the many, ubiquitous quantum-enabled technologies that demonstrate its mathematical precision. Yet conceptual descriptions of the theory vary widely and seldom sit comfortably. For example, some argue that probabilities encoded by quantum wave functions merely reflect limited knowledge of a system, like dice under a cup. Others hold that they represent a strange indeterminacy that persists until observed, like dice that continue to roll until someone looks at them. Yet others claim the probabilities are an illusion, and every possible outcome occurs in a different branch of a multiverse. Popular interpretations include QBism, Everett’s Many Worlds Interpretation, the pilot wave theory of Louis de Broglie and David Bohm, spontaneous collapse theories, relational QM, and of course the still-dominant, if misleadingly named Copenhagen interpretation. With the proven mathematical formalism, why do so many divergent, often contradictory interpretations of QM coexist?
In this course, we will discuss the key interpretational concerns of quantum mechanics and sample how different interpretations try to address them. Aside from answering the vexing “measurement problem” and Schrödinger’s cat paradox, what other features of quantum mechanics does a convincing interpretation need to account for? Does quantum mechanics offend our mundane intuitions by necessity, or does the weirdness result from having inadequate interpretations? What cherished metaphysical assumptions might we give up in order to resolve certain difficulties? What new difficulties would that introduce? If even contemporary, fundamental physics harbors such heated controversy, what does this tell us generally about the practice of science and the nature of scientific knowledge? Readings may include work by Albert Einstein, Niels Bohr, Richard Feynman, N. David Mermin, Lee Smolin, Evelyn Fox Keller, Karen Barad, David Z. Albert, Tim Maudlin, and other physicists and philosophers. Quantum mechanics has hitherto changed the world in various ways; isn’t the point of physics to interpret it?
