Descartes’ greatest student is Baruch Spinoza, a Jewish philosopher born and raised in 17th-century Amsterdam. Spinoza’s near ancestors had been expelled from Spain and Portugal, after centuries of off-and-on persecution in those places. Eventually, the Sephardic Jews, as this group came to be known, settled in the Low Countries. In this chapter, we examine the philosophy Spinoza erects in this unstable political atmosphere. Persecution and exile are ways of dividing the social body, separating out the pure and the impure. Spinoza would have none of this. He constructs a worldview in which everything is radically one and interconnected. As such, he is the real founder of what we might broadly call ecological thinking. Crisis, fragmentation, exile and persecution lead to a vision of wholeness and complex interconnection.