This chapter explains Spinoza's conceptual framework to illustrate how it can be employed to address the question of when should information be classed as private and when should it be communicated that is central to privacy. Spinoza explains both inadequate and adequate knowledge in terms of human encounters with other things in the world. The idea that the state may feel that they can impose "adequate knowledge" upon others in order to improve their lives is a criticism that Berlin levelled at Spinoza. The chapter explains what it means to have an immanent ethics of privacy, extends this to an examination of the political implications of Spinoza's ethics and then applies the ethics to specific areas of privacy. Spinoza's politics are based upon the idea that human bodies are similar enough to each other that what people know of their encounters with the world is useful for one another.