M’Naughten Rule
In evidence, to provide to the judge the qualification of a witness (particularly an expert witness) or a document or other piece of evidence which assures the court of the talent and experience of a witness or the authenticity of the document or article. example: a medical report cannot be introduced unless the physician who wrote it testifies that he wrote it, or a photograph must be authenticated by the photographer or by testimony that it truly reflects a particular place or event. an expert witness is qualified by testimony as to experience and training.