"A verbal art like poetry is reflective; it stops to think. Music is immediate, it goes on to become"

W.H. Auden, the celebrated poet and critic, brings out the inherent aesthetic nuances between two beautiful forms of art - poetry and music, in his insightful comparison. When Auden says that 'poetry is reflective; it stops to think', one can comprehend his perception of poetry as a medium of introspection and debate. Poetry demands an active interaction between the poet and their thoughts, ideals, and emotions. It is a dialogue, an examination of sentiments, a distillation of personal philosophy or social commentary, where every word and phrase is carefully selected, molded, and arranged to create an impactful narrative.

Each line of a poem often contains profound meanings, layered metaphors, and deep-seated emotions that may require ruminative reading to completely understand and appreciate. Furthermore, poetry serves as a mirror to the poet’s soul and, in a broader context, to society and human nature as a whole. Hence, Auden's statement encapsulates the way poetry forces us to 'stop and think', regardless of whether we are readers or creators.

Contrastingly, Auden juxtaposes music’s innate technicality and flow against poetry's introspective nature. He describes music as 'immediate', and 'going on to become', highlighting how music embodies and transcends the present moment. Unlike poetry, music doesn't need to 'stop' to resonate with its audience or create an emotive response. It unfolds with each note, carrying listeners along, reaching out to them directly, and often instantaneously, hitting the chords of their emotions.

Music doesn't need deciphering or in-depth contemplation to appreciate or enjoy. It connects with the audience with a raw immediacy, regardless of the language or culture, making it an expression of universal emotions. It 'goes on to become', signifying the dynamic and ever-evolving essence of music. It transforms itself while transforming its audience. From classical to modern, from instrumental to digital, music has continued evolving while maintaining its direct, unpretentious, and innate emotional appeal.

In succinct terms, Auden's observation brilliantly captures the philosophical depth and reflective nature of poetry whilst delineating the unmediated emotional appeal and evolutionary continuity of music.