On impossibility in law

The use of impossibility in the legal domain is a very broad and multifaceted phenomenon, as is shown by the constant references made to legal maxims like impossibilium nulla obligatio est. Legal scholars trace their use back to the ought-implies-can principle, which is the subject of wide debate in ethics, though of little use in legal terms given that the features of impossibility in law depend far more on law itself, especially its pragmatics. Impossibility should, indeed, be of great interest for the general theory of law, which tends however to ignore it. The main purpose of this paper is therefore to clarify what impossibility is in law and outline a typology of its different applications. We will find, for example, that it may denote the lack of a right or a deficiency in the effectiveness of the legal system and can also refer to categories like unreasonableness, necessity, uncertainty, and so forth.