Can wavefunctions collapse?
Many-worlds predicts/retrodicts that wavefunctions appear to collapse (See “Does the EPR experiment prohibit locality?”), when measurement- like interactions (See “What is a measurement?”) and processes occur via a process called decoherence (See “What is decoherence?”), but claims that the wavefunction does not actually collapse but continues to evolve according to the usual wave-equation. If a mechanism for collapse could be found then there would be no need for many-worlds. The reason why we doubt that collapse takes place is because no one has ever been able to devise a physical mechanism that could trigger it. The Copenhagen interpretation posits that observers collapse wavefunctions, but is unable to define “observer”. (See “What is the Copenhagen interpretation?” and “Is there any alternative theory?”) Without a definition of observer there can be no mechanism triggered by their presence. Another popular view is that irreversible processes trigger collapse. Certainly wavefunctio
