This chapter focuses on the history of the concept of ‘human nature’, through examining major philosophical and religious accounts. It discusses the distinction between ‘psychological and natural kinds’. Plato distinguished between soul and body, two radically different kinds of entity: the soul – which defines the person – is immortal, made from leftovers of the cosmos-soul travelling between the stars and the human body it temporarily inhabits. Aristotle, a student of Plato, identified psyche as the animating force in the universe, which distinguished living from non-living things. In The Passions of the Soul, Rene Descartes totally separated the body and soul; the former now seen mechanistically. Thomas Hobbes rejected Descartes’ dualism: the mind is wholly material and embodied in the brain. The central concept in Hobbes’ theory of the passions is conatus. For Friedrich Nietzsche, the will to power is the single most important explanatory principle of nature/human nature.