Abstract

In “The Uses of Argument” Toulmin introduces a number of concepts that have become popular in argumentation theory, such as data, claim, warrant, backing, force, field, and, most fundamentally, the concept of a “logical type”. Toulmin never defines the concept of a logical type or a field very clearly, and different interpretations can be found in the literature, either reconstructing what Toulmin has in mind, or revising his concepts to suit other concerns. A natural history of these concepts is not my concern. I will analyse logical types according to what Toulmin uses this concept for, namely to raise a problem with deductive logic and motivate its replacement with the Toulmin model. I will argue that a logical type and the distinction he draws between different logical types resembles distinctions made in logical positivism between the directly and the indirectly verifiable, and the problem raised is, in essence, the positivist’s problem of how indirect propositions can be justified on the basis of direct propositions. I will show that Toulmin makes a straw man of the positivists’ own solution to the problem and hence does not prove there to be an adequate motivation for replacing deductive logic with the Toulmin model.