Exclusion covering damage resulting from the instability or natural deterioration of the object itself, as opposed to an external accidental cause.
Inherent vice refers to a property's tendency to deteriorate through its own constitution, a material that cracks, a pigment that turns, a support that warps, an old textile that grows fragile. Policies exclude it because an insurer covers accident and not aging, failing which it would fund routine conservation rather than a contingency. The exclusion is well founded in principle and formidable in practice on the oldest objects, since it removes from cover what is most likely to happen to them. Distinguishing natural deterioration from transport-induced aggravation presupposes knowing the exact prior state, hence the weight given to joint condition reports.
The inherent vice question resurfaces when very high value fragile objects are lent, the public indemnity arrangement sometimes admitting a more favorable reading of the exclusion to secure prestigious loans.
vice propre, inherent vice, défaut inhérent