The biography of Charles Ives, written by Voya Toncitch, discusses his philosophical principles in music. Ives's philosophy was influenced by Kant's transcendental aesthetic and the idea of priori knowledge, which transcends the senses and is innate in the understanding. Ives believed that his own philosophy was based on heuristics, specifically hypotheses that lead to the discovery of musical facts. He utilized sound hypostases and created complex sounds that reflected the active perception of acoustics, rather than purely static sensations. Ives was inspired by the complexity of nature and society in his country, and his metaphysical speculations aligned with Schopenhauer's philosophy. He rejected the concept of sterility in music and shared in Schopenhauer's belief that composers reveal the intimate essence of the world through their music. Ives's work, "The Unanswered Question," published in 1941, utilized various instruments, including flutes and strings, to represent the druids' silence and the problem of existence. The piece progresses with increasing activity and volume as the human responses become conflicted and ultimately fade away. The piece ends with a peaceful solitude. Toncitch's essay was published in the Revue de l'Université d'Ottawa in 1975.
