Sartrean and Kleinian theories provide an account of human nature which foregrounds internal division and negation. It is helpful here to recall how Jean-Paul Sartre's best-known work of philosophy, Being and Nothingness, employs the concepts of the "for-itself" and the "in-itself" to distinguish two modes of being. As a starting point we can see that the "for-itself" refers to consciousness, and the "in-itself" refers to matter. However, Sartre's theory is more complex than this. For example, consciousness may assume an idea of itself as being thing-like, of a fixed and determinate nature. Sartre challenges this as a form of false consciousness, an evasion of freedom and a denial of the truth contained in the very concept of the "for-itself". However, this does not mean that consciousness can deny its inherent relationship with the "in-itself". We cannot deny material factors, including the self's relation to the body. For Sartre, in Being and Nothingness, we must understand the internal relationship between the "for-itself" and the "in-itself". Thus, negation is placed at the heart of being, and the Sartrean model, like Kleinian theory, believes that knowledge requires engagement with an ineradicable division within human nature. ¹