 Today, informal logic is “informal” rather than “formal” primarily because it studies arguments as they occur in natural language discourse, and not in formal languages of the sort that characterize formal logic. The latter are notable for their rigorously defined syntax, semantics, and grammar, and precisely defined proof procedures. In contrast, arguments as they occur in real life discourse are notable for their use of everyday language; for the many different norms that apply to them in different contexts; and for the diverse ways of making meaning (using pictures, facial expressions, non-verbal sounds, music, etc.) that they employ. 