The distinction between justify a conclusion from rule and justify it when no rule is resumed to elucidate some aspects of legal activity. This distinction found in Rawls a spokesman that incisively pointed out its importance for the legal practice. Before him, however, Hume (A Treatise of Human Nature), Mill (A System of Logic), Ryle (The Concept of Mind) and Toulmin (The Uses of Argument), among others, had already made relevant considerations to the topic. The distinction serves as motivation to split the field of argumentation practice, particularly of the legal argument, into two classes, namely, arguments of first and second order. In the arguments of second order, a rule operates in the manner described in the Toulmin model, in the arguments of the first order, characterized by the absence of rule, by weighting of reasons, substantiated on general principles, moral values, political interests, religious considerations and corporate claims. Some examples illustrate the distinction. It is argued that the logical basis of this distinction is based on the concept of rule as exclusionary reason, within the meaning established by Joseph Raz.