"Determinism often is taken to mean causal determinism, which in physics is known as cause-and-effect. It is the concept that events within a given paradigm are bound by causality in such a way that any state (of an object or event) is completely determined by prior states" -- from wiki Does it follow that the next state of a system is already mapped out by the history built up of prior states. Thus without observation or interference we can determine the next state to happen, if we had all the information of prior states? Can an event occur without any observation/measurement thereof? This question seems nonsensical , but when one talks of observation/measurement / events in QM they are crucial in understanding their definitions WRT determinism. How does QM relate to determinism , if everything can be predicted given that we have collected all the information available to us in the universe. I'm quite confused on how it fits together? I.E. QM and determinism. .