Synchronicity is the experience of two or more events, that are apparently causally unrelated or unlikely to occur together by chance, that are observed to occur together in a meaningful manner. The concept of synchronicity was first described by Swiss psychologist Carl Gustav Jung in the 1920s.
The concept does not question, or compete with, the notion of causality. Instead, it maintains that just as events may be grouped by cause, they may also be grouped by their meaning. Since meaning is a complex mental construction, subject to conscious and unconscious influence, not every correlation in the grouping of events by meaning needs to have an explanation in terms of cause and effect.