Musical expression  Musical expression is the art of playing or singing with a personal response to the music. At a practical level, this means making appropriate use of dynamics, phrasing, timbre and articulation to bring the music to life. Composers may specify these aspects of expression to a greater or lesser extent in the notation of their musical score. The nature of musical expression has also been discussed at a theoretical level throughout of the history of classical music. One common view is that music both expresses and evokes emotion, forming a conduit for emotional communication between the musician and the audience. This view has been present through most of musical history, though it was most clearly expressed in musical romanticism. However, emotion's role in music has been challenged on occasion by those like Igor Stravinsky who see music as a pure art form and expression as an irrelevant distraction. In the Baroque and Classical periods of music, music (and aesthetics as a whole) was strongly influenced by Aristotle's theory of "mimesis". Art represented the perfection and imitation of nature, speech and emotion. As speech was taken as a model for music, composition and performance in the Baroque period were strongly influenced by rhetoric. According to what has become known as the theory of affect, a musician was expected to stir feelings in his audience in much the same way as an orator making a speech in accordance with the rules of classical rhetoric. As a result, the aim of a piece of music was to produce a particular emotion, for instance joy, sadness, anger or calm. The harmony, melody, tonality, metre and structure of the music worked to this end, as did all the aspects under the performer's control such as articulation and dynamics. As Johann Joachim Quantz wrote, Baroque composers used expressive markings relatively rarely, so it can be a challenge for musicians today to interpret Baroque scores, in particular if they adopt a historically informed performance perspective and aim to recreate an approach that might have been recognised at the time. There are no universal rules in doing so, but there are some broad principles. Looking at the rhythm of a piece, slow rhythms tend to be serious while quick ones tend towards light and frivolous. In the melodic line, small intervals typically represented melancholy while large leaps were used to represent joy. In harmony, the choice of dissonances used had a significant effect on which emotion was intended (or produced), and Quantz recommended that the more extreme the dissonance, the louder it should be played.