  The categorical language Spinoza uses in the Appendix to Part I provides explicit support for this interpretation of IIIp9: “men act always on account of an end, viz. on account of their advantage, which they want.” Moreover there are other important passages in Spinoza’s works which are strongly compatible with the interpretation of Spinoza as an orthodox egoist. These include Ethics IVp8d, and his political writings, especially Ethics IVp36s2, and his Political Treatise, chapter 2)