The biggest problem in the Many Worlds theory of quantum mechanics  Summary and Q&A
TL;DR
This video discusses the problem of probability in the many worlds theory and proposes a more intuitive understanding of probability that aligns with the experience of randomness in quantum mechanics.
Questions & Answers
Q: How does the many worlds theory handle the issue of probability in quantum mechanics?
In many worlds theory, the occurrence of different outcomes in separate worlds eliminates the concept of randomness. However, the experience of randomness in quantum mechanics suggests that probability should still be present in the theory.
Q: Why can't probability be assigned based on the number of worlds where an outcome occurs?
If probabilities were assigned based on the number of worlds where an outcome occurs, inconsistencies would arise when different measurement methods are used. This contradicts the principles of probability and leads to an unsatisfactory explanation of randomness.
Q: How does the proposed understanding of probability in many worlds theory incorporate uncertainty?
The proposed understanding of probability focuses on the experience of the observer. Each observer can only experience one outcome, creating uncertainty about which world they will end up in. Probability is then defined as the expected proportion of experiencing a particular outcome in repeated experiments.
Q: Is the proposed understanding of probability applicable only to many worlds theory?
No, the proposed understanding of probability, known as the Born rule, applies to both many worlds theory and the Copenhagen interpretation. It is a consistent and mathematically derived rule that explains the experience of randomness in quantum mechanics.
Summary & Key Takeaways

The many worlds theory suggests that when a measurement is made in quantum mechanics, different outcomes occur in separate worlds, eliminating the concept of randomness.

However, the experience of randomness in quantum mechanics suggests that probability should still play a role in many worlds theory.

The video explores the issue of assigning probabilities in the many worlds interpretation and proposes a new understanding of probability that incorporates uncertainty.