The aim of this essay is to bring the philosophical theology of St Augustine, and in particular his anthropology, into fuller dialogue with contemporary psychology, and to examine how psychology and theology might benefit from such an engagement. A further aim is to show that intra-psychic accounts of Augustine's Confessions are insufficient on cultural-psychological, philosophical and theological grounds. To the extent that the modern concept of ‘pure nature’ is incompatible with Augustine's philosophical theology, attempts to develop naturalistic intra-individual, psychological accounts of spiritual change will necessarily be limited once the full ‘ecstatic’ orientation of human existence is factored out. The picture of the person that emerges from naturalistic accounts of any mystical theologian may be plausible within the framework of a classical modern, post Cartesian concept of scientific rationality, and potentially useful for some purposes, but it will be over simplified and never wholly sufficient to account for the potentialities of human existence.