Introduction

“Your strength as a rationalist is your ability to be more confused by fiction than by reality.”

—Eliezer Yudkowsky, “Harry Potter and the Methods of Rationality”

This is a book for physicists and students of physics. It does not try to teach you quantum mechanics. I assume you have already studied it, or perhaps you are currently taking your first course on the subject. I also assume you are confused. This is a very safe assumption, because everyone who has studied quantum mechanics is confused, myself included.

Part of this is for good reasons. It really is a very complicated subject. There also is much that we simply do not know. Confusion is hard to avoid when so many fundamental questions have no answers.

Unfortunately, some of it is also for bad reasons. Let me be blunt: a vast amount of utter nonsense has been written about quantum mechanics. Any article about it in the popular press is as likely as not to contain at least a little nonsense. If there is only a little, be grateful. That makes it one of the better ones.

But the problem goes much further. There also is much nonsense written by physicists. Some can be found in textbooks. Some is found in research papers by people who study quantum mechanics professionally. I doubt any other scientific field has produced half so much confusion and misunderstanding even among people who work in the field.

The goal of this book is to help you become less confused. That does not mean you will fully understand the subject. I cannot offer profound insights about the nature of reality. There is far too much that we simply do not know. But you will at least have a clearer understanding of what is and is not known. I will also try to explain and clarify some of the more common sources of confusion.

I intend this book to be a perpetual work in progress. I hope that with time, I too will become less confused and I can update the book accordingly. I also cannot rule out the possibility that some of what I write is itself nonsense. If so, I can only hope someone will find a polite way to point it out to me so I can fix it!