Every aspect of music is explained through the five propositions. The first proposition says that the fundamental property of all music is sound. All over the world, music is distinguished by the sound emanating from singers. In other words, music cannot exist without a sound aspect. Not all sounds can be musical sounds. A musical sound is a sound whose primary identity is a musical identity and is normally referred to as pitch. Other sounds such as noises, ambient sounds and speech are excluded from musical sounds. For every musical tone there are four fundamental properties. These are frequency, duration, attitude and timbre. In musical terms the four properties are called pitch, length, volume and sound quality respectively. It is also important to note that tones are defined by the surrounding musical environment. The relationship between tones and musical environment gives rise to chords, melodies, textures and rhythms. Tones have different meanings depending on their cultural significance. For example, a piece of music has a different cultural meaning when used in a fast food commercial than when used in a religious context. Such music captures different types of listeners' imaginations. All sounds have the potential to become musical tones if they are assorted and arranged in a systematic way. A good example of such music is John Cage's 4'33, whose absence of sound led to the assortment of chair squeaks, coughs and air conditioning hums that spawned a musical.