In his Political Treatise, Spinoza repeatedly compares states to human beings. In this interpretation of the comparisons, I present a progressively more restrictive account of Spinoza’s views about the nature of human beings in the Ethics and show at each step how those views inform the account of states in the Political Treatise. Because, like human beings, states are individuals, they strive to persevere in existence. Because, like human beings, states are composed of parts that are individuals, states' parts also (...) strive to persevere in being. Finally, because in states, as in human beings, a change to the power of striving of a part can be at the same time a change to the whole that differs in kind, strong states can be bad for their citizens and states that serve their citizens well may nevertheless be weak. Spinoza’s principal project in the Political Treatise is to design states that are stable and good for their citizens. This account of the comparisons shows why that project is so difficult: one cannot design a good state simply by designing a stable state. (shrink)