In simple terms, if you believe in the Schrödinger equation and its modern probabilistic interpretation as described in the Schrödinger picture, then at first it seem that there is no strict causality to the outcome of experiments.
People have then tried to recover that by assuming that there is some inner sate beyond the Schrödinger equation, but these ideas are refuted by Bell test experiments, unless we give up the principle of locality, which feels more important, especially in special relativity, where faster-than-light implies time travel, which breaks causality even more dramatically.
If something does a quantum jump, what causes it to decide doing so at a particular time and not another? It is expected that a continuous cause would have continuous effects.
This concern was raised immediately by Rutherford while reviewing the Bohr model in 1913 as mentioned in The Quantum Story by Jim Baggott (2011) page 32.
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Causality refers to the relationship between causes and effects, where one event (the cause) leads to the occurrence of another event (the effect). In other words, causality implies that certain conditions or events result in or contribute to the happening of other conditions or events. Understanding causality is essential in various fields, including philosophy, science, statistics, and everyday reasoning, as it helps in making predictions, understanding phenomena, and making informed decisions.