Philosophy for Children (P4C) is a collective (teaching) practice which has been shown to foster language abilities, logic and creativity in children. While these benefits obtained with the P4C oral practice have been well documented, philosophical writing received little attention. The aim of this paper is to examine which conditions better promote the quality of philosophical writing. Six writing conditions were proposed to a total of 317 students between the age of 12 and 13 from various socioeconomic backgrounds. These conditions varied according to the media (image, dialogue, key words) and the topic (dichotomous, not dichotomous). The quality of philosophical writing was assessed according to several indicators reflecting linguistic, logical and creative performances. Results show that the quality of philosophical writing depended on the media and the topic which were proposed, indicating different types of language planning across conditions. Interestingly, the image (vs. dialogue or key words) encouraged creativity, detected by a more frequent use of metaphors, while distinctions between concepts were more frequently made from a dichotomous (vs. not dichotomous) topic. The functions of metaphors and examples are discussed in parallel with gender and school effects obtained in this study.