In this article I will analyse the relationship between subjectivity and truth in Michel Foucault’s sayings and writings between 1981 and 1984, with an emphasis on its relevance to the problematization of spirituality and its developments in the notions of self-care, conversion, asceticism and logos in the context of his «trip» through ancient philosophy. The article explores the richness of this relationship, emphasizing the subjectivation of truth through the notion of paraskeue. Understood as the set of practices necessary and sufficient to allow us to be stronger than anything that can happen, it operates as a practical matrix of action. This matrix is considered true when it permeates rational conduct, making the subject strong enough to face events that can hurt or weaken him. In conclusion, the subject of philosophical spirituality is a subject of ascetic actions in permanent preparation for the adversities of existence.