Psychology as a science of life

William James famously defined psychology as the science of mental life. Much ink has since been spilled over the concept of the mental, but less so over the notion of life. In this article, I argue that psychologists should address life as an equally important concept. First, I briefly articulate Aristotle’s idea of the soul (or mind) as a life principle. Second, I argue with reference to Wittgenstein that the division between the living and non-living is more basic and important than that between mind and matter. Third, I introduce the work of the philosopher Hans Jonas, who made the phenomenon of life central to his existential interpretation of biological facts and argued that nature should be seen as a source of value. My conclusion is that psychology as a science of life must be a biographical science—a science of what it is to live a life.