In Totem and Taboo, Freud introduces the term taboo as a Polynesian word that means both sacred, consecrated and uncanny, dangerous, forbidden, unclean. The taboo seems to have a strength all its own. "Taboo restrictions have no grounds and are of unknown origins." (Standard Edtion, vol 13, p.18) nor are they subject to question.
Freud describes taboo as a magical power which is inherent in persons and spirits and can be conveyed by them through the medium of inanimate objects. He compares their dangerous charge to electricity and infection.
In a jab at "enlightened" society, Freud identifies the workings of the Kantian "categorical imperative" with the taboo. According to Freud, it too "operates in a compulsive manner and rejects any conscious motives."
For Mary Douglas, taboos are reactions to events that seriously defy established lines of classification.