## Choices in Multiverse

Posted on October 9, 2014 — 2 Minutes Read

Quantum mechanics is odd. For decades physicists have been studying it intensively, and with countless experiments, what we can say about particles of the quantum scale is that they seem to exhibit a probabilistic nature, that you can only describe a particle at the quantum scale by a wave function, that gives off the particle’s position, momentum, and other physical properties, as probabilities. Human-scale objects have a definite location at any given time. But particles at the quantum scale? Before a measurement, it can anywhere, and nowhere, at the same time, and when you actually do a measurement, the particle will pick one out of all the possible outcomes.

Some physicists say the wave function collapses, from all possible outcomes, to a single reality. This collapse is known as the Copenhagen interpretation. Some don’t believe that the wave function collapses at all, and to reconcile the probabilistic quantum superposition with the deterministic reality, before and after the measurement, the many-worlds hypothesis is introduced. The idea is that the particle is indeed in every location that it could possibly be. The measurement does not impact the wave function so that all the possibilities collapse to a single reality, but it splits the outcomes, each outcome in its own parallel universe, and we are in one of them. Say a particle can be on the left or on the right. When you make a measurement, the many-worlds hypothesis says that, you split the world into two universes. In one universe you find the particle on the left, in another, you find it on the right. If this is true, then it means every time I make a decision, there is another me choosing otherwise, in another parallel universe. I will for sure remind myself of this next time I am making a difficult decision, for I will in any case both be right and wrong.