The article studies the verbal manifestation of critical thought in a school context. Four modes of thought - logical, creative, responsible, and metacognitive – accompanied by six epistemological perspectives, are studied from 1,730 pupils turns to speak analyzed in eight class groups. The pupils dialog about freedom. Quantitatively and gradually the collective thought gives the lion's share to the manifestation of logical, followed by creative and then responsible thought, and very little to that of metacognitive thought. The study reveals a significant developmental effect for logical and responsible thought – to the advantage of the girls. While each mode of thought evolves following its own developmental path, the epistemological congruence that emerges between the logical and responsible modes of thought on the one hand and responsible and creative on the other seems perhaps debatable. The results lead to a pedagogic proposal which consists in proposing to introduce a cognitive activity of doubt, not spontaneously adopted by the pupils, to favor the advent of a form of critical thinking more balanced as concerns the modes of thoughts of which it composed.