Abstract
Assuming the validity of the Many Worlds Interpretation of quantum mechanics (MWI), we examine the possibility of changing the past by memory erasure. We find that while observers cannot change the probability of experiencing certain outcomes, they can nevertheless randomize past events and thus end up in a different sector of the multiverse. We also discuss Tegmark's quantum suicide thought experiment and show that, contrary to conventional wisdom, it {it cannot} be used by an observer to test the validity of the MWI for herself.
Saibal Mitra