Auguste Comte suggested that the main sciences could be grouped into a hierarchical ordering that reflected their objective characteristics (viz., generality, dependence, and complexity). In particular, the empirical sciences could be placed in the following order: astronomy, physics, chemistry, biology, and sociology. Although his idea was initially discredited in the sociology of science, subsequent research indicates that the conjecture has considerable empirical merit. Significantly, that research inserts psychology between biology and sociology, with significantly more proximity with biology. After replicating the earlier findings using new measures, the metatheoretical basis for the hierarchical arrangement is then examined. The article closes with suggestions for further empirical and theoretical research on psychology's placement in the hierarchical arrangement.