Substitutes for the soul included the self, personality, and the brain. “Self” kept the older issues alive without metaphysical baggage. Calkins’ “self-psychology” held that the self was the basal concept in psychology, and that soul was unnecessary. Allport found that “personality” enabled psychology to address topics vital to soul. The brain is the most significant substitute for the soul. Lashley sought to translate introspective findings into a physicalist language. Lashley retained terms such as meaning and self-consciousness, but articulated them in terms of stimuli and responses of the nervous system. Hebb dismissed introspection altogether. His “cell assembly” theory proposed neural networks as organized patterns of responses to stimuli. Thought is the organized activity of the nervous system. Given the emphasis on organization of neural firing, therein is the brain a substitute for the soul, since in the older psychologies, soul was a principle of form or organization.