“The rise of the waltz,” explained Curt Sachs in the World  
History of the Dance , “was a result of that longing for truth, 
simplicity, closeness to nature, and primitivism, which the last 
two-thirds of the eighteenth century fulfilled.” In the century of 
jazz we are likely to overlook the emergence of the waltz as a 
hot and explosive human expression that broke through the 
formal feudal barriers of courtly and choral dance styles.

     There is a basic principle that distinguishes a hot medium 
like radio from a cool one like the telephone,  or a hot medium 
like the movie from a cool one like TV. A hot medium is one that 
extends one single sense in “high definition.” High definition is 
the state of being well filled with data. A photograph is, 
visually, “high definition.” A cartoon is “low definition,” simply 
because very little visual information is provided. Telephone is a 
cool medium, or one of low definition, because the ear is given a