<p>Revisions are proposed to the taxonomic model of human
motivation of Forbes (2011) in order to incorporate a heretofore missing fourth
life domain, the spiritual. The growing literature on spiritual motives is systematically
reviewed in accordance with literature review standards for theory development
(Templier & Paré, 2018) focusing on the objective of identifying
comprehensive theoretical systems that explicitly incorporate the spiritual
domain as one of a limited set of human life domains. The structure of the Forbes
model is contrasted with thirteen theoretical systems that explicitly
incorporate the spiritual as a fourth life domain. Consistent with the Forbes
model, the spiritual domain is proposed to consist of three modes of existence
(Being, Doing, Having) represented as justice motivation, moral motivation, and
transcendental motivation, respectively, as well as both promotion and
prevention goals within each of the three motives. Empirical evidence is
reviewed in support of a revised heuristic device wherein the Spiritual domain
is closely linked with the Intrapsychic and Interpersonal domains, but not the
Instrumental domain, resulting in a pyramidal structure and corresponding set of
five testable hypotheses.</p>