Ratiocination; step-by-step philosophical reasoning, as opposed to intuition.
Digression.
An idea that engenders a compulsive or irrational preoccupation, or the preoccupation thereby engendered.
The quality of being obsessed.
Influence or control by evil spirits without possession.
An activity or entity that inspires a compulsive and potentially unhealthy fixation, or the fixation thereby inspired.