He who gives a thing by mistake has a right to recover it back; but, if he gives designedly (with knowledge of the facts), it is a gift.

Explanation

(English-origin maxim.) A gift made under mistake of fact may be recovered, but a gift made deliberately and with full knowledge is irrevocable — intent and knowledge at the time of giving determine whether restitution lies.

Where this applies

• A woman accidentally sends a $5,000 payment to the wrong account, thinking it was her landlord's — she has the right to recover it because the transfer was made under a mistake of fact, not as a deliberate gift.
• A man knowingly gives his neighbor a valuable painting as a housewarming present with full awareness of its worth — he cannot later demand it back, because a gift made deliberately with knowledge of the facts is irrevocable.
• An estate executor mistakenly distributes a family heirloom to the wrong heir, believing the will named that person — the correct heir can recover it because the transfer was made by mistake, but if the executor had distributed it knowingly and intentionally, it would stand.