We are usually looking at the world of very large objects, planets, stars, clusters, and galaxies. At the other end of the scale is the quantum world where electrons, protons, quarks exist. The stuff that the large world is made up.
The quantum world is a strange place. Particles may be in two places at once or may be blocked by a barrier and suddenly be on the other side of the barrier. Also, they may become entangled so that if something happens to one the other is “aware” of it no matter the distance between them.
The book “What Is Real” by Adam Becker is an attempt to look at this world and trace the history of trying to explain it. Early in the 20th century quantum mechanics was able to develop equations which showed how the quantum world worked. The equations were able to predict outcomes and were very useful in developing applications. Unfortunately, they didn’t show why or answer the question of where the quantum world ends and our every day world begin?. Also, why does measuring/observing events change what is happening. An initial attempt to explain this was called the Copenhagen interpretation which was the basis of understanding for many years. However, any scrutiny of the Copenhagen interpretation left some wondering. Essentially, it said “Shut Up and Calculate” which meant the equations worked and lots of applications came out of them so don’t rock the boat and worry about why.
The book shows how the Copenhagen interpretation was king and that you better not question it. Some dared and were blacklisted. Journals refused to print any challenges to it. This has gone on for a long time but slowly other explanations have been discussed.
So for a historical review of where we are and all the characters involved this book is a good, but heavy, read. Don’t expect an answer at the end.