Commenting on the Torah's charge "to be holy, since I the Lord your G-d am holy" (Vayikra, 19:2) the Ramban explains that it is not enough to keep the laws of the Torah. One can do so meticulously and still be a "scoundrel with the permission of the Torah". Torah law gives us a framework for life, but one who so desires can technically stay within that framework while nonetheless violating the basic goals of the Torah. What we often call the spirit of the law—observing the intent of the law and not just its letter—is the mark of holiness.
By dint of the fifth amendment to the Constitution, US citizens are protected from being forced to give self-incriminating testimony; pleading the fifth is a common refrain in many a courtroom. Jewish law goes one step further; it forbids the giving of self-incriminating evidence. Ein adam masshem aztmo rasha, a person cannot turn himself into an evil person (Yevamot 25b). Thus, one who admits to having killed someone cannot be convicted based on his own testimony.
The Talmud as a whole, and especially the Mishna, is first and foremost a vast corpus of Jewish law. Yet in studying this wide-ranging text, one would be hard-pressed to find any material on Jewish legal theory. Jewish law is primarily case-based, and a legal theorist would find the Talmudic approach most unusual.