The Probabilistic Nature of Quantum Mechanics
When I open up the Book Modern Quantum Mechanics by Sakurai and Napolitano and skim through it, I find the defintion (1.97) which is:
" Probability for a' = |<a'|α>|^2 , provided that |α> is normalized. "
And then later on the statement:
"The probabilistic interpretation (1.97) for the squared inner product |<a'|α>|^2 is one of the fundamental postulates of quantum mechanics, so it cannot be proven."
Which means that the probabilistic interpretation of the inner product is one of the fundamental postulates of quantum mechanics.
On the other hand I have seen this episode of Star Trek: The Next Generation where Worf travels through the many worlds of quantum mechanics and in one of them he is married to Deanna Troi.
So my question is: Which one is the correct source to decide if quantum mechanics is probabilistic in its nature?