Fenwick also argued that recent advances in neuropsychiatry and, in particular, in neuroimaging, would render obsolete much of the criminal law in that descriptions of brain pathology would enable the courts to apportion blame in a more precise manner than has been possible before. However, analyzing mental states defenses on the basis of mens rea is of doubtful usefulness due to the variations in the term's meanings over the years and because not everyone agrees that psychiatric defenses operate by addressing mens rea at all. In addition, the existence of an observable brain condition would not eliminate the role of mens rea in court. Medical evidence will continue to be relevant, not to determine whether the defendant was responsible but to indicate whether the defendant suffered from a disorder that impaired the ability to choose. 18 references and list of 6 law reports