I wonder who came up with this idea.
Causality conceives of the world as being held adrift by chains of causal relations, forming a partial order of events/states of affairs/acts/mechanisms.
The cause necessarily results in the effect.
The main problem: how to define necessity? How do we distinguish between coincidence and a causal relation?
Some people cannot conceive of infinite partial orders,
and without good reason, assume a first cause.