A friend who went missing after a hiking trip, a kidnapped sibling who was never found, loved ones who got swept away in a tsunami without ever having their bodies recovered, or a spouse with Alzheimer's disease who no longer recognizes you or remembers your shared memories - these are ambiguous losses which can be harder to cope with because the grieving process is interrupted by a glimmer of hope that, maybe, the victim is still alive somewhere out there. Dr. Johnben Loy explains more or ambiguous loss, and why certainty and closure is such a basic human need.