by Leanne Ogasawara
Nobel laureate Steven Weinberg had a wonderful piece in a recent edition of the New York Review of Books about "the trouble with quantum mechanics."
Trouble? You ask….?
Well according to science writer Tom Siegfried, "Quantum mechanics is science’s equivalent of political polarization." He says:
Voters either take sides and argue with each other endlessly, or stay home and accept politics as it is. Physicists either just accept quantum mechanics and do their calculations, or take sides in the never-ending debate over what quantum mechanics is actually saying about reality.
This is to draw attention to the fact that as the mathematical models become increasingly more sophisticated in representing a foundational picture of physical reality, the conclusions that can be drawn from the picture become "impossibly weird." Such weirdness is what led to Schrodinger's cat, for example. Or later on to the weirdness called "entanglement" and the multiverse; both which we can safely describe as being, "extreme weirdness."
To understand what physicists mean when they call something "weird," Weinberg pointedly contrasts the situation in quantum mechanics to the ever-reliable consolation that is classical Newtonian physics; in which one can quite accurately calculate where a ball will land if its velocity and direction are known. Not so in our new universe; for in the crazy upside-down world of quantum mechanics no one can say for sure where an electron will be if it is measured–only where the probability wave is most intense.
Even Einstein lost his nerve at this point, famously saying, "God does not throw dice." And Weinberg wonderfully describes how both Schrodinger and Einstein distanced themselves from quantum mechanics later in their careers for just this reason; as the observational results have led particle physicists into saying the damnedest things.
And interestingly this weirdness eventually led to the two different approaches to the issues, so wonderfully described by Tom Siegfried above. Before reading Weinberg's piece I wasn't actually aware that particle physicists thought in terms of "realism" versus "instrumentalism;" as this is a dichotomy that I associated with an older period in the history and philosophy of science.