The TM technique involves the use of a silently-used sound called a mantra, and is practiced for 15–20 minutes twice per day. It is taught by certified teachers through a standard course of instruction, which costs a fee that varies by country. According to the Transcendental Meditation movement, it is a non-religious method for relaxation, stress reduction, and self-development. The technique has been seen as both religious and non-religious; sociologists, scholars, and a New Jersey judge and court are among those who have expressed views on it being religious or non-religious; some have characterized the surrounding movement and TM organizations as cult-like while others have argued to the contrary. The United States Court of Appeals upheld the federal ruling that TM was essentially "religious in nature" and therefore could not be taught in public schools.