“Can I say ‘shit’ in my head?” This is a question my five-year-old grandson posed to his mother. Her response, obviously a wise one, was “Go for it.” She didn’t want him to be troubled by the inevitable intrusion of a taboo word into his thoughts. A five year old has enough to worry about.
But we seem predisposed to believe our thoughts are powerful and important both negatively and positively. Maybe the Judaeo-Christian morality that emphasizes the proper interior disposition is more a reflection of this predisposition than a cause of it.
North American popular culture is obsessed with the power of thought as an instrument of self-improvement. Norman Vincent Peale’s classic The Power of Positive Thinking did much to popularize the notion that we can think our way to happiness and prosperity. New Age gurus go so far as to claim that we create our own reality with our thoughts. Usually such powers are associated vaguely with the term “quantum” (http://www.csicop.org/si/show/quantum_quackery)
The neurologist Sam Harris has pointed out we are all subject to an unstoppable flow of thoughts. The meditative techniques of all major religious traditions are aimed at interrupting this brain chatter. Harris, an atheist, is a proponent of secular, non-religious meditation. (https://www.samharris.org/blog/item/how-to-meditate)
So the child’s innocent question “Can I say ‘shit’ in my head” becomes the adult’s urgent question: “How do I get this shit out of my head?”