Erwin Schrödinger And The Quantum Revolution
John Gribbin’s book appropriately treats the wave-particle duality of quantum mechanics as a metaphor for the man-scientist duality in Schrödinger’s life.
Schrödinger received the Nobel prize in 1933 along with Paul Dirac for his wave equation, which neatly described the puzzling spectrum of the hydrogen atom, earlier explained only by the ad hoc quantisation rules proposed by Niels Bohr.
However, it was Bohr who had the last laugh. The accepted understanding of the “waves” in the Schrödinger equation is that they are probability waves. But they can interfere like water, sound or light waves. This interference of probabilities has experimental consequences: one can see the interference pattern in the two-slit experiment. However, the interference pattern disappears when we observe the system to find out which slit the electron went through. Left on its own, a quantum mechanical system such as an electron evolves according to Schrödinger’s equation. But when we measure it, it “collapses” (the “wave” collapses into a “particle”). This collapse of the wave-function drove Schrödinger to desperation. As a challenge to it, he proposed his famous thought experiment known as “Schrödinger’s cat”. Left on its own, the cat evolves into a state where it is apparently both dead and alive at one instant of time. But when we observe it, it is either alive or dead; never both.
This philosophical inclination marked Schrödinger as an unconventional physicist. The aversion of other physicists to philosophy led him to call them assess and himself one of the few sane persons around. His philosophy was greatly influenced by Arthur Schopenhauer (who brought the Upanishads to the West through the German translation of the Moghul prince Dara Shukoh’s Farsi translation). Indeed, the rumour goes that Schrödinger used the idea of advait (literally, “not two”) as a seduction strategy in the numerous affairs he recorded in a diary! (Of course, these affairs were with the consent of his wife, who herself had various lovers.)
Anyway, it was this philosophical inclination that led him to write his influential book What is Life? and other less influential essays on free will and determinism. Though not a Jew, he left Nazi Germany for ethical reasons (and nearly landed in India).
The biographer John Gribbin is himself well-known and certainly, he has done all the usual research. However, the book falls significantly short.
While the facts are there, the excitement is missing. Also, the research is inadequate. In this book and an earlier one (Schrödinger’s Kittens), Gribbin advocates Cramer’s transactional interpretation of quantum mechanics. That transactional interpretation is based on the Wheeler-Feynman absorber theory and Gribbin seems oblivious to the fact that there are serious flaws in the Wheeler-Feynman theory, as this reviewer pointed out long ago. Just ignoring that criticism may suit science defined as something done by an exclusive club of scientists, but it does not suit the idea of science as truth, which is how it is popularly understood.
The book should have touched upon other interpretations of quantum mechanics closer to Schrödinger’s philosophical concerns. Thus, Advait Vedantists took over many Buddhist arguments. For example, the Buddhist notion of time (paticca samuppada) is closely linked to the Buddhist logic of four alternatives (catuskoti). The third alternative on this logic allows the possibility that “the world is both finite and not-finite”, so one can guess that it would suit quantum mechanics (“the cat is both dead and not-dead”). Indeed, logic depends upon the nature of time. For example, if time has a structure, the resulting logic would not be binary. In actual fact, such a structure of time may arise, at the microphysical level, from closed loops in time, for example. To relate a closed loop in time to the cat metaphor, suppose that we have a time machine (or a correct version of the Wheeler-Feynman theory), and use it to send a dead cat back to the past when it was alive. Then there will be an “instant” of time when the “same” cat is both dead and alive. Indeed, this reviewer has shown, in his own structured-time interpretation of quantum mechanics, that probabilities based the logic of such a structured time, similar to Buddhist logic, correspond to quantum probabilities.
Of course, such a logic and notion of time are contrary to all Western philosophy founded on the parochial belief that logic is universal. But science must be prepared to dump bad philosophical assumptions, even if it means the demise of Western philosophy. Exploring this possibility would have been particularly apt in the context of Schrödinger who sought a broader unity of thought. Unfortunately, Gribbin has chosen to play safe and follow the conventional line of the Western history and philosophy of science, which typically erases or marginalises the non-West.
CK Raju is research professor at the AlBukhary International University, Malaysia. He advanced the structured-time interpretation of quantum mechanics.