Rule-skepticism claimed that talented lawyers, using a well-developed system of legal rules, could produce arguments resting on accepted premises of that system and supporting both a result and its opposite. The arguments produced could be fashioned for internal coherence and consistency with prior decisions. Part I offers a critique of four versions of legal formalism, the descendant of rule-skepticism. The four versions of legal formalism are classical doctrinal formalism, moral philosophy, law and economics, and the sociology of professions. Part II provides a discussion of fact-skepticism, a legal philosophy that claims it is impossible for an analyst to capture past actions in enough detail to allow confident assessments of what happened or might happen in the future. The critical legal studies movement is viewed as a descendant of fact-skepticism, the authors say. Fact-skepticism focuses on law-in-action, a perspective that is concerned with how things look to a court and the way things really were. After a look at criminal procedure from the perspectives of rule-skepticism and fact-skepticism, it is concluded that neither legal philosophy suffices. They claim that the rules of criminal procedure are attempts by authoritative decisionmakers to express their concepts of the world. 108 footnotes.