Our presentation questions the cognitive input of metaphor in critical thought and collective reasoning as practiced by participants to a “Community of Philosophical Inquiry", now "CPI". Introduced by Mathew Lipman (1995), and supported by UNESCO for its positive implications for language and cognitive development, educational success, and social relations and behavior at school and beyond (Daniel, 2015; Tozzi, 2007), CPI is a discourse practice in which participants discuss and argue from an initial philosophical questioning. Participation to a CPI involves both conceptualization and abstraction. Metaphor in language use is a powerful and robust cognitive tool for conceptualization, cognitive development, language acquisition, and learning (Fauconnier, 1997; Gentner et al., 2001; Goswami, 1996 ; Hofstadter & Sander, 2013; Lakoff & Johnson, 1985, 1999). A metaphor is the result of a mapping between the cognitive underlying of everyday action in the physical world, spatial thinking, and language in its broader sense, i.e., including co-speech gesture. Indeed, studies on the so-called 'metaphoric gesture' demonstrated its potentiality to represent abstract concepts in expository discourse (Calbris, 2003, 2011; Cienki & Müller, 2008; Johnson, 1987). Turning to language development, children aged over 6 years both verbalize metaphor and produce metaphoric gestures during spontaneous talk when giving explanations, arguing, and discussing concepts (Colletta, 2004; Colletta & Pellenq, 2009). Yet, we have no clue as to the cognitive input of metaphor in collective reasoning. Would linguistic and gestural metaphor play a role in the emergence of critical thought, i.e., questioning and discussing concepts and judgment premices (Daniel, 2007; Lipman, 1995) ? We lack information on the collective resonance of ideas expressed via metaphor during talk and discussions. This study was designed to tackle the question within an observational study on CPI. In our view, thanks to analogical properties that gives some salience to metaphoric contents, metaphor expressed by a participant during a discussion could initiate new developments in the on-going collective reasoning, thus generating new ideas, new concepts and new arguments. In order to demonstrate the key role of both gestural and verbal metaphor in collective reasoning, we analyzed video recordings of three CPI collected in a middle school in Grenoble (France) within an on-going project (Philéduc). Discussions were conducted by teachers and/or tutors trained in philosophy for children with grade 6, 7 and 8 students. The topics discussed were thought, life and death, and savagery. We listed all metaphorical expressions, whether verbal or gestural, and we studied the resonance of metaphor across speech turns and modality (gestural>verbal>gestural). Our results suggest that the use of metaphor does enhance generalizations, favor language reflexive use, and help implement rational and critical thinking among students. Références: Calbris, G. (2003). L’expression gestuelle de la pensée d’un homme politique. Paris, Editions du CNRS. Calbris G. (2011). Elements of Meaning in Gesture. Amsterdam/Philadelphia. John Benjamins Publishing Company. Colletta, J.-M. (2004). Le développement de la parole chez l’enfant âgé de 6 à 11 ans. Corps, langage et cognition. Hayen, Belgique: Mardaga. Colletta, J.-M., Pellenq, C. (2009). Multimodal explanations in French children aged from 3 to 11 years. In N. Nippold & C. Scott (Eds.), Expository Discourse in Children, Adolescents, and Adults. Development and Disorders (pp. 63-97). New-York: Erlbaum, Taylor & Francis. Daniel, M.-F. (2007). L’apprentissage du philosopher et le processus développemental d’une pensée critique dialogique. In M. Tozzi (dir.). Apprendre à philosopher par la discussion. Pourquoi? Comment? (pp.123-137). Bruxelles : Éditions De Boeck Université. Daniel, M.F. (2015). Mes élèves philosophent-ils ? Des critères pour saisir la pensée en développement. In E. Auriac-Slusarczyk & J.M. Colletta : Les ateliers de philosophie: une pensée collective en acte. Clermont-Ferrand : Presses Universitaires Blaise Pascal (pp.335-357). Fauconnier, G. (1997). Mappings in thought and language. New-York, Cambridge University Press. Gentner, D., Holyoak, K.J., Kokinov, B.N., Eds. (2001). The analogical mind. Perspectives from cognitive science. Cambridge, MA: M.I.T. Press. Goswami U (1996). Analogical reasoning and cognitive development. Adv Child Dev Behav, 26, 91-138. Hofstadter, D., Sander, E. (2013). L’analogie, cœur de la pensée. Paris : Odile Jacob. Johnson, M. (1987). The body in the mind: The bodily basis of meaning, imagination and reasoning. Chicago: Chicago University Press. Lakoff, G., Johnson, M. (1985). Les métaphores dans la vie quotidienne. Paris : Editions de Minuit. Lakoff, G., Johnson, M. (1999). Philosophy in the flesh: the embodied mind and its challenge to Western thought. New York : Basic books. Lipman, M. (1995). À l'école de la pensée. Bruxelles : De Boeck. Tozzi, M. (2007). Apprendre à philosopher en discutant : pourquoi et comment ? Bruxelles : De Boeck.