This chapter sketches out the journey Spinoza makes from formal being to the concept of infinite machine understood as the inexhaustible source of a post-foundational fostering power in the world.I show the genetic link between the mind as fosterer of affects, and the city of such minds as the fosterer of multitudes.Spinoza (echoing Hobbes and Machiavelli) feels that the methodology appropriate to multitudes must begin from the perspective of power.I claim that Spinoza's Tractatus politicus, deploys such a methodology in which the multitude forms a particular moment of the political process.I advance an alternative methodology, still focused through the lens of power, which discloses the possibility of the super-multitude. Introduction-Spinoza and foundationsHow can the arch-determinist Spinoza even be thought in relation to a post-foundationalism which prizes radical contingency, the eternal un-grounding of every attempt to construct a foundation (Machart 2007)?For that matter, how can Spinoza be thought as an author who offers at least in some respects a non-totalizing and post-foundational theory of cosmopolitanism?One angle of approach is to follow the manner in which Spinoza constructs an excessive un-grounding at the level of what he terms modes, defined as affections of substance, or that which must be conceived through and in another.We cannot possibly do justice to the real depth of Spinoza's metaphysical insights here, 2 but in this preliminary section will sketch out the journey he makes from a formal being to the concept of infinite machine understood as the inexhaustible source of a nourishing, fostering power in the world, and from this to dual ideas of the mind as fosterer of affects, and the city of such minds as the fosterer of multitudes.In the subsequent sections we will argue that while an analysis of modes is appropriate to affects, Spinoza (echoing Hobbes and Machiavelli) feels that the methodology appropriate to multitudes must begin from the perspective of power.We claim that Spinoza's unfinished work, the Tractatus politicus, deploys such a methodology in which the multitude forms a particular moment of the political process.In the final substantive section we advance an alternative methodology, still focused through the lens of power, which we hope accentuates further the currency of Spinoza's political theory.