A more thorough explanation:

Definition: Inscrutable fault is a term used in maritime law to describe a situation where a collision occurred due to human error, but no responsible party can be identified.

For example, if two ships collide and it is clear that the collision was caused by human error, but it is impossible to determine which party was at fault, the collision would be considered an inscrutable fault.

This term is important in maritime law because it allows for a fair and just resolution to be reached even when fault cannot be assigned to a specific party. It acknowledges that accidents can happen even when all parties involved are acting with due care and attention.