Causal chain
In philosophy, a causal chain is an ordered sequence of events in which any one event in the chain causes the next. Some philosophers believe causation relates facts, not events, in which case the meaning is adjusted accordingly. Some philosophers believe that causality may not exist if determinism is true, as causality is merely the observation that one event precedes another, or that there is a pattern throughout spacetime in which events of one similar type tend to correlate with events of another similar type (that is, the mass-energy distribution in spacetime has an information theoretic 'pattern ' where car crashes tend to be correlated with injury, say). There may be no ultimate reason for why a chain of causality occurs the way that it does beyond the fact that a chain of causality exists. The fact that certain events seem to 'cause' other events is the recognition of a pattern in the structure of spacetime and the mass-energy that exists in spacetime, which is ultimately either due OR an instantiation of the laws of physics. Note: Stating that causality does not exist may be a bit misleading, as one would have to Define what is meant  by 'causality' - it may be that causality is dependent upon counterfactual definiteness, that is, A causes B because, if A did NOT occur, then B would not occur (i.e.: A is necessary for B) AND because A is sufficient for B. It may be possible that causality is ultimately a meaningless concept (if one rejects counterfactual definiteness for instance), but that causal chains are still a valid concept (as they would merely be chains of events).