Lawyers love Latin. Perhaps that is why they use the term mens rea to describe the simple concept that one should not be subject to punishment unless one has acted in a blameworthy way. Traditionally, the criminal law required a showing of mens rea (which is Latin for a guilty mind) for one to be convicted of an offense. One had to knowingly or at least recklessly act in a morally blameworthy way to be subject to criminal punishment.