What is Real? by Adam Becker
My background in physics and in quantum mechanics in particular, are two courses at the university and a lot of reading. I don’t claim to understand everything I read, the math are really hard, but I understand the fundamental notions, I think. Mostly, I am curious about quantum mechanics, it’s mysterious, exciting and strange.
Quantum theory is the most successful scientific theory humanity has ever devised. It is the physics of tiny but it goes well beyond that. It explains virtually everything about the universe. The problem with quantum physics is what is telling us about the physical world around us.
Ok, I will try to explain this as I understand it- and I am not sure I understand it completely. The problem in quantum mechanics is that particles exist normally in a superposition of possibilities described by the wave function, which basically means that, when we are not observing, the particles exist as mathematical possibilities rather than one actual object, like how we experience and observe objects in reality.
But, how the particles go from a mathematical state of possibilities when we are not observing to the state of a physical object when we observe? Something happens when we look, strange as it may sound the very act of watching affects the observed reality. And what do we mean by measurement? When I measure something, does this measurement applies only to me? Is it a measurement valid only when humans measure? We are missing something here, a mechanism of how this occurs. Well, this is the measurement problem.
The most famous version of the measurement problem is Schrodinger’s cat. Yes … yes… this cat again, which is both alive and dead, until we open the box. Of course, the cat cannot be both dead and alive until we open the box, that doesn’t make any sense. It is not the way the world works. But that doesn’t mean that quantum physics is wrong either, it simply means that quantum physics is not yet complete.
Although every physicist agrees that quantum physics works, a bitter debate has raged over its meaning for the past ninety years, since the theory first developed. One position in that debate was developed by Niels Bohr and Werner Heisenberg- the so-called Copenhagen Interpretation- takes the observer out of the equation because as Bohr argued, it is unscientific and meaningless to talk about unobservable things.
Others-the minority-disagreed. The Copenhagen Interpretation is unsatisfying, both scientifically and philosophically, they argued. They wanted to understand what is going on in the world, how measurement works. These talented physicists developed alternative approaches to quantum physics in order to explain what is going on in the world without sacrificing any of the theory’s accuracy. This quest for the meaning of quantum physics, this strange relationship between theory and reality, as well as the story of the scientists who set out to resolve the ‘measurement problem’ by challenging and providing viable alternatives (including my favourite many-worlds interpretation) to Copenhagen interpretation, is the subject of this book.
What is Real? is what happened over the past 90 years in the development of quantum physics and the philosophy underpinning the stories that were told about quantum physics. It’s a fascinating, accessible, still unfinished story.