For the first 40 years of his life, Hartley pursued the ideals and philosophical principles of American transcendentalism. He shifted radically from this approach after the First World War. Instead of embracing subjectivity, he honored rational intellect and objectivity. Toward the end of his life, he returned to a passionate belief in the subjective self. Patricia McDonnell analyzes Hartley's beliefs and artistic practice in the context of the cultural and political realities that deeply affected the man and his times.