# Probability in many-world theories

### APA

Araujo, M. (2019). Probability in many-world theories. Perimeter Institute. https://pirsa.org/19040047

### MLA

Araujo, Mateus. Probability in many-world theories. Perimeter Institute, Apr. 16, 2019, https://pirsa.org/19040047

### BibTex

@misc{ pirsa_PIRSA:19040047, doi = {10.48660/19040047}, url = {https://pirsa.org/19040047}, author = {Araujo, Mateus}, keywords = {Quantum Foundations}, language = {en}, title = { Probability in many-world theories}, publisher = {Perimeter Institute}, year = {2019}, month = {apr}, note = {PIRSA:19040047 see, \url{https://pirsa.org}} }

**Collection**

**Subject**

A common criticism directed against many-world theories is that, being deterministic, they cannot make sense of probability. I argue that, on the contrary, deterministic theories with branching provide us the only known coherent definition of objective probability. I illustrate this argument with a toy many-worlds theory known as Kent's universe, and discuss its limitations when applied to the usual Many-Worlds interpretation of quantum mechanics.

I'll also argue that subjective probabilities are unproblematic in the many-worlds setting by showing how the usual decision-theoretical axioms apply there, and finish by showing that together with a proper definition of measurement they suffice to derive the Born rule.