In Schopenhauer's The World as Will and Idea, he argues that the will manifests itself in humans and the intellect is the will's slave. Schopenhauer states that the will does not have knowledge itself and depends on the intellect for knowledge. He includes the intellect in the physical category along with the body and argues that the will is metaphysical. The will, he states, is unconscious in itself and thus requires an intellect to be its object in order to act, "As there can be no object without a subject, so also there can be no subject without an object," (101, 2). The will is the master, the intellect its slave, "Clearly the master here is the will, the servant the intellect," (104, 1). He uses various examples, such as the concept of hope, the comparison of animals to humans, and the conjuring of memories, to establish his premise that the will...