It is called the principle of indemnity.
Explaination:
It is one of the basic principles of insurance, which is applicable only to the non-life category of insurance, as the life of human being cannot be ascertained in terms of money.
This principle ensures to make good the loss of the insured and bring back the insured in the same position as he was prior to such loss. This principle ensures that the insured does not make a profit out of insurance policy. The insured can claim the amount equivalent to loss when full value insurance is taken of the subject matter. In case the subject covered is less than the total amount, the average clause is applied.