Super­po­si­tion

Super­po­si­tion means that the state of a quantum system can be descri­bed as a state encom­pas­sing multi­ple possi­bi­li­ties. This does not imply the simul­ta­neous posses­sion of contra­dic­tory proper­ties; rather  it is a complete state descrip­tion from which proba­bi­li­ties of diffe­rent measu­re­ment outco­mes can be derived. A measu­re­ment yields a single, definite result. Prior to measu­re­ment, only proba­bi­li­stic predic­tions are meaningful.

Super­po­si­tion challenges the classi­cal notion of systems posse­sing prede­ter­mi­ned, well-defined of proper­ties. Possi­bi­li­ties and relati­onships become consti­tu­tive of what we observe, while classi­cal defini­ten­ess emerges only through inter­ac­tion with the surroun­ding environment.