"The Layout of Arguments" by Stephen Toulmin
From RhetorClick
In “The Layout of Arguments,” Stephen Toulmin’s thesis is that a new framework is needed for argumentation, as an alternative to the syllogism. The framework (or layout) he proposes involves a claim made due to some data, a warrant (often implicit) given to support the inference of the claim from the data, possibly a qualification added to the claim along with conditions of exception, and backing supplied to provide sufficient grounds for a warrant. Toulmin claims that the syllogism is too ambiguous because, for instance, universal premises (such as “All men are mortal”) do not properly distinguish between warrant and backing. Additionally, with a syllogism one cannot always tell whether a universal premise is true only in theory or in existential, empirical fact. Toulmin explains that logicians have too long relied on the syllogism and that in doing so they have forced arguments into a mold that doesn’t take into account subtle distinctions.