Legal Fiction. Believing or assuming something that is not true is true. Used in judicial reasoning for avoiding issues where a new situation comes up against the law, changing how the law is applied, but not changing the text of the law.
An assumption or supposition of law that something which is or may be false is true, or that a state of facts exists-which has never really taken place. New Hampshire Strafford Bank v. Cornell, 2 N. H.324; Hibberd v. Smith, 07 Cal. 547, 4 Pac. 473, 56 Am. Rep. 720.A fiction is a rule of law which assumes as true, and will not allow to be disproved,something which is false, but not impossible. Best, Ev. 419.These assumptions are of an innocent or even beneficial character, and are made for the advancement of the ends of justice. They secure this end chiefly by the extension of procedure from cases to which it is applicable to other cases to which it is not strictly applicable, the ground of inapplicability being some difference of an immaterial character. Brown.Fictions are to be distinguished from presumptions of law. By the former, something known to be false or unreal is assumed as true; by the latter, an inference is set up,which may be and probably is true, but which, at any rate, the law will not permit to be controverted.Mr. Best distinguishes legal fictions from presumptions juris et de jure, and divides them into three kinds.