This chapter makes the claim that the mystery of personhood is the heart and driver of Tallis’ atheistic humanism. In other words, as can be easily demonstrated from his writings on humanism, Raymond Tallis is a personalist—at least in the broad sense that personalism is usually defined by its most serious defenders. Even without an elaborate string of citations from his work, those familiar with his writings will readily concede that the central themes of Tallis’ philosophical anthropology, namely embodiment, intentionality, explicitness, and so on, always refer to the person or the self as the unifying agent who possesses or exercises these uniquely human qualities. In the first part of this chapter, I will show how Tallis’ deconstruction of scientism clears the ground for the existential intuition of selfhood or “explicitness” at the heart of his positive depiction of the person. In the second part of this chapter, I will put Tallis’ work in conversation with Christian personalism to suggest that this religious humanistic framework provides a more plausible grammar for the mystery of personhood.