Introduction
Let me start by a question that may look a bit strange at first glance: “To your opinion, what is a tomato: a vegetable or a fruit?”. People generally respond by saying that it is a vegetable. For botanists, however, tomato is a fruit, as it is the ovary, together with its seeds, of a flowering plant. It is thus a fruit, or more precisely, a berry. The term “vegetable” has even no botanical meaning, and is purely a culinary term.1 For centuries, one of the scientists’ main efforts is to try to “categorize” objects of the environment and to explain relationships, differences, and common points between them. However, objects are not so easily put into categories, and the definitions of categorizes evolve and change following new data or evidence. In our daily life, we, as laymen and laywomen, use categories that do not always fit with the ones the scientists have developed. Moreover, some objects of the reality can be considered as “ambiguous,” as they share characteristics of two or more categories.
It is this kind of phenomenon that some researchers in education and pedagogy take as a starting point for designing pedagogical activities in teaching sciences. Their main assumptions are twofold: starting from an ambiguous object can lead learners in science to explore the specificities of the categories that are linked to the phenomenon; and starting with a kind of “controversy question” (is A part of X or Y?) may also allow participants to enter into an argumentative and dialogical work that is at the heart of scientific activity. It is one of these pedagogical scenarios or cases that I would like to present in this chapter. It is called “Digalized Euglena2”, and is based on an inquiry-oriented and socio-constructivist pedagogical perspective, using argumentation as an exploratory and learning tool. In order to sustain and facilitate the dialogical processes, the activity is mediated by a computer-mediated learning environment called Digalo that provides a graphical map of the ongoing discussion. The case is constructed around the Euglena cell that presents interesting ambiguous characteristics with both vegetal and animal properties: it shows, for instance, an autotrophism function (like plants that “nourish” themselves via photosynthesis) and, under certain circumstances, a heterotrophism function, absorbing and digesting dissolved organic matter in the water (like animals). From a scientific perspective, the Euglena cell is part of the Protista kingdom of living that gathers all the mobile and unicellular living beings together.
My epistemological position in this chapter is not the one of a teacher in science nor even a researcher in teaching science, but rather the one of a psychosociologist in education interested in the contributions and limits of argumentation mediated by a learning environment in teaching sciences, and in its psychosocial issues.