What is Real?

I'm a sucker for Physics Weirdness books, so I picked up "What is Real?" without really knowing exactly what it would focus on. What it focuses on is this: quantum mechanics is the crowning achievement of 20th century science. Through elegant mathematics, it precisely predicts all sorts of directly unobservable phenomena with stunning accuracy. Most of its counterintuitive predictions have been proven true even though in some cases it's taken decades to develop the experiments with which to do it. All good. Just one nagging problem: the "measurement problem" in which any direct measurement of quantum phenomena causes the Schrödinger Equation wave function to collapse.

In simpler terms, before a subatomic particle is measured for momentum, location, or any other parameter, it (according to the math) exists all over the place with a wide range of physical attributes...the likelihood of these values is assigned a probability, not a discrete value...until you make a measurement. It's fine...all the math works and predictions can be accurately made which is all you need for practical applications like building a nuclear reactor or a transistor. But what does it mean for a particle to exist in multiple places at once until you "look" at it? Forgetting the math, what's physically happening?

Early quantum physicists, led by Niels Bohr, adopted what's known as the "Copenhagen Interpretation" in which it's declared that asking what's physically going on before a quantum measurement happens is a non-sensical question; it has no real-world meaning. You can't question what's happening prior to the measurement. This has been turned into a short-hand phrase used to summarize the Interpretation: "shut up and calculate." Naturally, this "don't ask" position leaves some physicists with a bad taste in their mouth. Those who have insisted on looking anyway were assigned heretic status for years. Those few who tried had their academic careers ruined. It's the third rail of physics.

The book does a good job of guiding the reader through the history of those rebels who have questioned Copenhagen and put forth some possible explanations for what's physically happening in this Forbidden Question Zone. Two biggies are the theory of Pilot Waves (which provides an explanation for how photons simultaneously behave as particles and waves) and the Many Worlds theory which holds that every action in the universe results in splits where all possible outcomes occur. The latter is fun to think about (especially in application to sci-fi stories) but seems ridiculously complicated. Physicists don't like inelegant complications in their theories. However, these alternate explanations are plausible in that they seem to solve some long-standing problems. Though they've gained some ground, they remain largely heretical theories, not widely embraced. They face the additional hurdle of not being testable. In science, that's a killer.

Where does that leave us? That's where the book's last third takes us: the realm of philosophy. Just when you thought that physics and math was triumphant, the author drags us into the realm of pontification. I've tried my hand at modern philosophy books, looking to see if it has anything to say to me. I've been disappointed every time. Maybe that's my failing, I don't know. All I can say is that it seems like a discipline that involves a lot of talking...but no results. It's what physics was before Newton.

What I learned was that philosophy is alive and well in some physicist corners. It was a substantial part of the backgrounds of scientists like Bohr, Einstein, and Mach. It informed their worldview in a way that would be surprising to a modern student of science. Author Becker believes that the split between philosophy and hard science that occurred when physics really took off in universities around the world after WW II was a mistake and that we need to return to a stronger liberal arts approach to science education. Because there's no other way to fathom the mysteries of the Measurement Problem. He makes the case that philosophy is the only way to approach the question of what's happening before the Schrödinger wave function collapses. I admit, I'm no philosopher and many people smarter than me believe Becker has a great point. I confess I wasn't at all convinced. I throw my lot in with Hawking who believed that philosophy has nothing to offer modern physics. It has a record of zero achievement. Becker disparages Hawking and others as being arrogant for taking this view.