Final answer:
Mahler was inspired by ancient Chinese poetry that he discovered in the German translation 'The Chinese Flute' for 'The Song of the Earth,' which reflects deep human emotions and existential themes similar to those portrayed in Romantic music.
Step-by-step explanation:
Gustav Mahler's inspiration for 'The Song of the Earth' (Das Lied von der Erde) was the deep human emotions and existential contemplation found in ancient Chinese poetry. Mahler discovered several Chinese poems translated into German by Hans Bethge in a collection called 'The Chinese Flute' (Die chinesische Flöte), which reflected on themes such as the beauty of nature, the transitory nature of life, and the mingling of joy and sorrow. Infused with the same kind of emotional intensity expressed in Romantic music and the emotional through time that Michael Tilson Thomas describes in his exploration of classical music, Mahler's work represents a poignant synthesis of Western symphonic tradition and Oriental philosophy.