This paper has two sections: first, I am going to analyze two criteria to differentiate between argumentation and formal demonstration. According to Perelman (Perelman & Olbrechts-Tyteca, 1989) argumentation is based on persuasion, and that is the reason why argumentation is polysemic, ambiguous; on the other hand, it is said that argumentation depends on the additional information that someone gives to us, while demonstration does not depend to the additional information. I will show that no criteria invoked to justify the disctintion (...) between demostration and argumentation is kept. In the second section I will show that persuasion is not necessarily associated to the speech act of argumentation, in the same way that the atempt of convincing is not necessarily associated with the act of asserting something. Thus, someone cannot use persuasion to define the argumentative exercise. (shrink)

In this paper I will present a visual method that I have created to demonstrate the validity of propositional arguments and predicates, based on the traditional Venn diagrams. This idea was born after becoming aware of how useful visual methods are in other scientific fields, such as geometrical representations of arithmetic and algebraic concepts. This method illustrates the relationship between propositional logic, predicate logic and set theory, and it can be used to explain linguistic semantic concepts such as synonymy, antonymy, (...) hyponymy, entailment, and lexical substitution. (shrink)