In a field known for startling ideas, the Many-Worlds Interpretation (MWI) of quantum mechanics may take the prize. It holds that parallel to our own world are a large number of other universes, almost identical to ours but with small variations. Copies of each of us inhabit a myriad of these worlds. But they are not us exactly; they share our past history, but they are different people who have unique futures. Although these realms are invisible and can’t communicate with each other, prominent physicists are convinced they must exist.

The Many Hidden Worlds of Quantum Mechanics is about why we should take the Many-Worlds Interpretation seriously, as arguably the best explanation of quantum mechanics, the science of matter and energy at the atomic and subatomic scales. In 24 fascinating lectures, Professor Sean Carroll of Johns Hopkins University guides listeners through the history, reasoning, and implications of this bold idea. He also covers alternate theories to Many-Worlds and unresolved questions in fundamental physics, making the course a thorough introduction to the current state of this exciting field.

Starting with classical physics, Professor Carroll explains how quantum theory overturned traditional ideas about matter and energy in the early 20th century. A consensus soon formed around a framework called the Copenhagen Interpretation, which rejected speculation about what was “really happening.” The Many-Worlds Interpretation in the 1950s was a reaction against this view, proposing that we take the basic equation of quantum mechanics seriously and go where it leads. It turns out it leads to Many-Worlds.