The rise of psychology over the past century has proceeded apace even in the absence of a unifying theory. The current state of the discipline is one where distinct sub-disciplines pursue compartmentalised interests based on specialist foci that address nuanced aspects of psychological activity in the human species. This commentary outlines the minimal ingredients of a grand theory of psychological activity that requires formulation at three levels of analysis. At the macro level, sociocultural contextual factors bear an influence on individuals and are more or less conducive to the expression of particular tendencies. At the micro level, phylogenetic tendencies influence psychological activity through neurochemical activity. At the meso level, individual dispositions are attuned to contextual demand through a process of changing mindsets to suit circumstances. At this strictly psychological level of activity, the ethical imperative facing the discipline is one that helps maximise psychological health and wellbeing in the face of adversarial conditions.