David Peat

Quantum Uncertainty 11a gap in a theory, to some experimental interference that had not yetbeen taken into account.Wolfgang Pauli, another of the physicists who helped to developquantum theory, put the counterargument most forcefully when hesuggested that physics had to come to terms with what he called “theirrational in matter.” Pauli himself had many conversations with thepsychologist Carl Jung, who had discovered what Pauli termed an “objectivelevel” to the unconscious. It is objective because this collectiveunconscious is universal and lies beyond any personal and individualevents in a person’s life. Likewise, Pauli suggested that just as mind hadbeen discovered to have an objective level, so too would matter befound to have a subjective aspect. One feature of this was what Paulicalled the “irrational” behavior of matter. Irrationality, for Pauli, includedquantum chance, events that occur outside the limits of causalityand rational physical law.The gap between Pauli’s irrationality of matter and Einstein’s objectivereality is very wide. What made this gap unbridgeable was aneven more radical uncertainty—whether or not an underlying realityexists at the quantum level, whether or not there is any reality independentof an act of observation.Heisenberg’s Uncertainty PrincipleThis disappearance of an ultimate reality has its seed in WernerHeisenberg’s famous uncertainty principle. When Heisenberg discoveredquantum mechanics he noticed that his mathematical formulationdictated that certain properties, such as the speed and position ofan electron, couldn’t be simultaneously known for certain. This discoverywas then expressed as Heisenberg’s uncertainty principle.When astronomers want to predict the path of a comet all theyneed to do is measure its speed and position at one instance. Given theforce of gravity and Newton’s laws of motion, it is a simple matter toplug speed and position into the equations and plot out the exact pathof that comet for centuries to come. But when it comes to an electron,things are profoundly different. An experimenter can pin down its