SILENCE describes the relative or total absence of audible sound, but also motionlessness. By analogy, the word silence may also refer to any absence of communication. The further meanings of silence can be calmness and tranquillity. Some people love this aspects of silence, as it is also part of meditation practice, and necessary for concentration as we read or write or give lectures or things like that. In contrast, the total absence of sound can make people be afraid, in an extreme they even loose orientation in space. Silence, also, has a double face, as silence describes an inner feeling, but also denotes a given condition of what is around us and what not. Marketing practice, for instance, presumes silence as a negative factor on consumption behaviour, instead, in music silence, as the so called "tacet", functions as an important effect for rhythm, tension, and drama. According to cultural norms, silence can be interpreted as a positive or negative essential in culture and life.