Jewish law recognizes a fundamental distinction between lost property and mislaid property.
One who encounters mislaid property not only need not pick it up, indeed one is prohibited from picking up the property, whether to find its original owner or to claim it as lost. The identical distinction is found in the common law. According to common law, one who places an item down deliberately has created some form of a bailment with the one on whose property the item is left. Jewish law resolved these issues by creating a presumption in favor of mislaid property. If doubt exists whether the article was deposited or lost, the finder should not assume possession.