Acknowledgements; List of abbreviations; Introduction: 'what corresponds to sensation'; Part I. Substantial Forms and Reality: 1. Reality and substantial forms in Descartes and Suárez; 1.1. Reality-containment and substantial forms in Descartes and Suárez; 1.2. Causation and substantial forms in Descartes and Suárez; 1.3. Descartes on the intelligibility of substantial forms; 2. Vis Viva and the essence of matter; 2.1. Vis Viva and quantity of motion; 2.2. Vis Viva and 'quantity of progress'; 2.3. Vis Viva and potential energy; 2.4. Potential energy and substantial forms; 2.5. Living and dead forces, primitive and derivative forces in Leibniz's Specimen Dynamicum; 2.6. The principle of sufficient reason and the intelligibility of substantial forms; 3. Leibniz on the law of continuity; 3.1. Leibniz on the law of continuity in mathematics; 3.2. Leibniz on the law of continuity in physics; 3.3. Leibniz's law of continuity and genus-species subordination; Part II. The Magnitude of Reality: 4. Reality and magnitude in Kant's Negative Magnitudes; 4.1. The validity of mathematical concepts in philosophy; 4.2. Negative magnitudes and real opposition; 4.3. Kant's main argument in Negative Magnitudes Section III; 4.4. Ground and consequence, and the law of continuity in Negative Magnitudes; 5. The category of reality and the law of continuity; 5.1. Kant's classification of laws of continuity; 5.2. Laws of continuity in Kant's Inaugural Dissertation; 5.3. The law of continuity's place in the table of categories; 5.4. The ground of sensation in the Inaugural Dissertation and in the CPR; 6. Objectivity and the quantification of reality; 6.1. Objectivity and the concepts of quality; 6.2. Why qualities should have quantities; 6.3. Intensive magnitudes and the anticipations of perception; 7. Reality, causation, and motion; 7.1. Reality and causation; 7.2. Simultaneous and instantaneous causation; 7.3. Reality and motion; 7.4. Reality, motion, and the moment of change; Part III. The All of Reality: 8. Metaphysical and mechanical laws of the continuity of alteration; 8.1. The continuity of alteration in the CPR; 8.2. The continuity of alteration in the MFNS; 9. The second analogy and the uniformity of nature; 9.1. The second analogy and the existence of empirical laws; 9.2. 'An unbounded diversity of empirical laws'; 9.3. The applicability of transcendental principles in experience; 10. Reality and the system of all possible empirical concepts; 10.1. Kant and Leibniz on the idea of a system of all possible empirical concepts; 10.2. Transcendental ideas and the concept of realitas noumenon; 10.3. Transcendental ideas and the pure use of reason; 10.4. Transcendental ideas and the property of continuity; 10.5. The transcendental ideas and the regulative principles of science; 11. Reality and the derivation of rgavitation; 11.1. Kant's example of genus-species subordination in the appendix to the dialectic; 11.2. Kant's example and the continuity of conic sections; 11.3. Kant's example and Newton's derivation of gravitation; 11.4. Kant on Newton and the objective validity of motion; 11.5. Kant on genus-species subordination and Newton's derivation of gravitation; Conclusion; Bibliography.