Fuzzy logic dates back to 1965 and it is related not only to current areas of knowledge, such as Control Theory and Computer Science, but also to traditional ones, such as Philosophy and Linguistics. Like any logic, fuzzy logic is concerned with argumentation, but unlike other modalities, which focus on the crisp reasoning of Mathematics, it deals with common sense reasoning; i.e., with approximate reasoning. Although the teaching of logic has formed part of mainstream education for many years, fuzzy logic is a much more recent inclusion. In this paper we emphasize the desirability of having illustrative examples related to students’ everyday activities, such as sports, in order to introduce fuzzy logic in higher education. Taking an example from cycling, we show, step by step, how to model an approximate reasoning regarding the choice of a ratio (a combination of freewheel and chainring) in order to advance more or less with each rotation of the pedals. Led by this example, a number of alternatives attending to the formal representation of the premises and the ways of inferring a plausible conclusion are analyzed. The choices made between alternatives are justified. We show that the conclusion inferred in the example is consistent with the models selected for premises and fuzzy inference and similar to that concluded by a human being.

The focus of this paper is the study of causality in both its crisp and approximate forms. Crisp causality is characterized by some properties and modalities and is related to semantic implications. This paper presents a program that extracts causal and conditional sentences with causal content from several texts. The examples extracted show that, even in scientific texts, causality can be imprecise or imperfect, as shown by the linguistic modifiers or the fuzzy quantifiers embedded in them. Quantum mechanics introduces imprecision in physics, but social sciences are the disciplines that show more circumstantial and imperfect links between cause and effect. In social sciences, there are two theoretical paradigms to understanding imperfect causality: (i) cause as an `ideal type', from Weber, (ii) cause as a `family resemblance predicate', from Anscombe, a follower of Wittgenstein's philosophy. Our work provides two short exemplifications of these paradigms using the causal or conditional sentences retrieved from texts of different genres.