Contingent contracts to do
or not to do anything if an uncertain future event does not happen can be enforced when the happening of
that event becomes impossible, and not before.
Illustration
A agrees to pay B a sum of money if a certain ship does not return. The ship is sunk. The contract can be enforced when the ship sinks.
Illustration
A agrees to pay B a sum of money if a certain ship does not return. The ship is sunk. The contract can be enforced when the ship sinks.