INUS condition

INUS condition stands for an "insufficient, but necessary part of an unnecessary but sufficient condition." John Mackie introduced the term in the 1960s.
Mackie uses the example of a house burning: There was an electric short circuit that caused the fire. There was flammable material nearby, which started to burn after the short circuit happened. He then tries to explain the statement: "The short circuit caused the fire", according to the INUS condition:
INUS conditions need prior experience: Only after you have seen a house burning after a short-circuit putting flammable material on fire several times can you deduce that it is indeed sufficient.