The “System of all principles of pure understanding” is the second of three chapters in the Analytic of Principles. It is preceded by the Schematism chapter, in which Kant provides schemata, or time-determinations (in effect, spatio-temporal meanings), for the pure concepts of the understanding such that they can then be applied to objects given in sensible intuition. It is followed by the Phenomena/Noumena chapter, which summarizes the restrictions on cognition that Kant has established so far, and draws out some consequences thereof, especially insofar as they make clear the mistakes of earlier philosophers such as Leibniz and Locke. Despite the clear significance of these chapters, however, it is the System that forms the core of Kant's Analytic of Principles. For it contains his most detailed and specific positive account of how the categories - whose existence and legitimacy were established in a merely global way in the Metaphysical and Transcendental Deductions - are to be applied to appearances - that is, to objects given to us in sensible intuition. It does so not only by arguing for particular conditions under which each category must be applied, but also by providing insight into what Kant thinks any spatio-temporally unified world of experience must be for us - namely, a plurality of substances that stand in causal relations of mutual interaction, a view that is radically different from Hume's empiricism, though it has important parallels with the views of several of his predecessors, such as Wolff, Crusius, and Tetens.