In the introduction to their volume, Massimi and Breitenbach observe that Kant’s philosophy of natural science is a flourishing domain of scholarship, within which the notion of a law is absolutely critical. Kant and the Laws of Nature, which contains thirteen chapters from top-notch, international scholars on the title topic, is hence a text of transparent value to researchers working in this burgeoning area. The volume is not, however, parochially limited to technical readings of Kant’s views on physics. It rather offers substantial treatment of some of the most pressing and knotted issues in Kant scholarship, more broadly. Chapters concern the unity of practical and theoretical reason, the positive role reason plays in the generation of knowledge, Kant’s conception of causality and answer to Hume’s causal scepticism, the theoretical grounding of natural laws in Kant’s general metaphysical picture, Kant’s legacy in the history of physics, organisms and teleology, and the unity of nature. While the commentator specializing in Kant’s theoretical philosophy or his conception of natural science will find the most of interest and use in the volume, almost any Kant scholar will find something edifying, illuminating and stimulating in this excellent book.
Notably, many of the chapters in the volume extend and elaborate their authors’ general research programmes, particularly those of Paul Guyer, Hannah Ginsborg and Michael Friedman. These chapters do not merely repackage stale ideas, however. The (relative) novice may use these chapters as introductions to the classic interpretations of contemporary giants in the field, while the expert’s understanding of the theories is enhanced by the extension and elaboration. I especially highlight Friedman’s contribution in this regard, as it connects his interpretation of Kant’s theory of physics with his work on neo-Kantian theories of science as well as his post-Kuhnian account of scientific change. Beyond augmenting the reader’s understanding of Friedman’s account of the Metaphysical Foundations of Natural Science (MFNS below), his chapter synthesizes the broad, Friedmanian corpus, to the scholar’s benefit.
In chapter 1, ‘Kant on the Unity and Diversity of Laws’, Eric Watkins develops a univocal, overarching conception of laws in Kant’s system which comprehends a priori and empirical laws of nature; moral laws; juridical laws; regulative, logical laws of reason; and cosmological laws. All such laws are unified insofar as they (i) bear necessity, which (ii) results from a spontaneous, legislative act. (The account is a further development of Watkins Reference Watkins2014.) Yet within these two defining constraints, there is wide room for divergences among laws. Particular laws may vary along three dimensions. Different laws may be necessary in distinct senses, as natural laws necessitate determinations of substances, whereas moral laws prescribe action. Laws result from legislative acts of separate spontaneous faculties: the understanding’s activity produces natural laws, whereas the regulative, logical laws of systematicity rest on the reflective power of judgement. Finally, laws vary according to the sort of legislative act involved: juridical laws require actual public legislation, while pure practical reason gives the moral law to itself.
Karl Ameriks’ chapter 2, ‘On Universality, Necessity, and Law in General in Kant’, similarly develops a comprehensive framework to capture the variability of laws in Kant’s philosophy before proceeding to develop further Watkins’ account of laws by handling various ancillary issues. Ameriks details nine dimensions along which laws of nature vary for Kant. This detailed account clarifies the philosophical backing for the different sorts of laws in Kant’s thought. Subsequently, Ameriks offers friendly amendments to Watkins’ account of laws, especially aimed at grounding the unity of natural and moral laws. For instance, Ameriks explains that, for Kant, in both theoretical and practical contexts, laws involve ‘determination’ (Bestimmung), which can refer either to the ‘characterization of a natural state’, or to the ‘rationalization of an action’ (p. 38). Thus, whereas the descriptive and prescriptive aspects of natural and moral laws, respectively, appear prima facie to connote a fundamental distinction between them, Ameriks reveals their inner unity.
In chapter 3, ‘Imperfect Knowledge of Nature: Kant, Hume, and the Laws of Nature’, Guyer elaborates his account of systematicity and the laws of nature developed in prior texts (see the first part of Guyer Reference Guyer2005). Guyer explains that knowledge of particular laws of nature qua necessarily true requires their embedding in a complete system of laws. However, such a complete system is beyond our (human) cognitive ken. We act and judge as if nature is systematic and contains particular necessary laws, but we cannot actually cognize this possibility. This implies that our actual knowledge of the laws of nature and their necessity is incomplete and always provisional. Guyer’s account hence reveals Kant to have epistemological concerns about the laws of nature distinct from Hume’s. Whereas Hume fretted about whether particular laws of nature would hold in the future, Kant allows for the possibility that our knowledge of the laws of nature will change in the future.
Ginsborg’s chapter 4 answers its title question, ‘Why Must we Presuppose the Systematicity of Nature?’ which emerges from the introductions to the Critique of the Power of Judgement (CPJ below). Her solution focuses on nature’s purposiveness and is grounded upon her insight that purposiveness is a form of normativity (see Ginsborg Reference Ginsborg2015). For Ginsborg, to claim that nature is purposive is to say that there are particular norms for judging about it. Nature’s purposiveness, thus understood, is then a condition for the exercise of judgement and, more fundamentally, bare empirical conceptualization in the following sense: our activity of empirical conceptualization involves the consciousness that we are subject to particular norms of classification, that is, we presuppose that nature is meant to be conceptualized how we conceptualize it. Insofar as our conceptualization involves or aspires to systematicity, we are thus committed to nature being so organized.
In the fifth chapter, ‘Empirical Scientific Investigation and the Ideas of Reason’, Rachel Zuckert demonstrates the provocative thesis that the transcendental ideas’ apparently negative epistemic and semantic aspects – their being representations of unknowable objects and ‘nearly empty’ – makes possible their positive contribution to empirical scientific knowledge. Insofar as the ideas lack completely determined content and cannot be instantiated in experience, they can only be employed as optimistic placeholders for the advance of empirical science. We conduct inquiry as if there is a soul – the single persisting, substantial basis for internal nature; as if there is a world whole – impelling us to incorporate ever more states of affairs into our scientific theorizing; and as if there is a God – who rationally legislates all natural phenomena. As we progress in scientific inquiry and revise our theories, these ideas remain as the optimistic placeholders that bring unity to practice; that leave us open to new possibilities dissimilar from our already comprehended empirical concepts; and that ward off cognitive idols, such as lazy reasoning.
Chapter 6, Thomas Teufel’s ‘Kant’s Transcendental Principle of Purposiveness and the “Maxim of the Lawfulness of Empirical Laws”’, examines the transcendental and epistemic dimensions of purposiveness in the introductions to CPJ. Teufel contends that commentators have largely conflated the transcendental and epistemic morals from the famous counterfactual scenario of cognitive chaos. That is, they take the transcendental principle of nature’s purposiveness derived from this case to be ‘concerned with’ the necessity of empirical laws of nature. According to Teufel’s reading, the transcendental deduction of nature’s purposiveness does not directly concern the necessity of empirical laws, and, conversely, the deduction does not take that necessity as evidence or as a premise, either. The transcendental principle provides mere minimal conditions on the cognizable order necessary in existence and only derivatively (and not on its own) supports the ‘Maxim of the Lawfulness of Empirical Laws’, which validates the presumption that contingent, empirical regularities are necessary causal laws.
Chapter 7, ‘Kant’s Necessitation Account of Laws and the Nature of Natures’, by James Messina, offers a persuasive account of the source of nomic necessity in Kant’s thought. According to Messina’s Necessitation Account (NA) – which is consonant with interpretations of causality and lawfulness from James Kreines, Watkins and Massimi – laws’ necessity derives not from the cognitive subject, but rather from the natures of things. In contemporary terms, Messina’s NA imputes to Kant a dispositional essentialism with respect to laws of nature, according to which essential properties of natural kinds include causal powers or dispositions that necessitate the laws of nature. Messina reinforces prior arguments for NA and ultimately makes the case for expanding the account. In particular, he contends that nature as a whole has a nature, or essence, that includes certain dispositions and causal powers that ground the transcendental laws of nature, namely those belonging to the System of Principles of the Critique of Pure Reason.
Massimi’s chapter 8, ‘Grounds, Modality, and Nomic Necessity in the Critical Kant’, sits comfortably next to Messina’s chapter in the third part of the volume, as she, too, attributes a sort of dispositional essentialism to Kant. (This account builds on Massimi Reference Massimi2014.) Massimi aims to address the Kantian Problem of Inference: succinctly, how can laws of nature necessitate particular states of affairs when they are prescribed by the understanding? Massimi’s account bases the natural necessity of empirical causal laws upon real grounds, essential powers and multi-track dispositions. According to this account, the understanding – via the principle of the Second Analogy – yields templates for causal connections, which are then filled in via experiments and observations that disclose a specific power (like the fundamental attractive force), based on a real ground (the nature of body), which causally grounds phenomenal behaviour (attraction between the Earth and Moon). Such filling in results in type-type causal judgements. We then derive particular token causal judgements by filling in ‘stimuli conditions’ under which the specific power operates, which then necessitate particular manifestations of the relevant disposition.
Chapter 9, Daniel Warren’s ‘Kant on Mathematical Force Laws’, resolves a tension in Kant’s account of the fundamental forces of matter. On one hand, Kant offers apparently a priori, mathematical laws governing the diffusion of the fundamental forces in the Dynamics of MFNS. An inverse-square law characterizes the attractive force while the repulsive force diffuses according to an inverse-cube law. Yet, on the other hand, Kant subsequently asserts that laws for the fundamental forces must not be based on a priori considerations but rather require appeal to the ‘data of experience’. Warren maintains that the mathematical descriptions of the laws demonstrate their unity and systematicity: both fall under ‘the universal law of dynamics’, according to which the intensity of a moving force is inversely proportional to the space into which it diffuses. However, genuine proofs of the force laws both require experience to verify the real possibility of the forces, while the inverse-square law demands additional experiential evidence regarding the attractive force’s action in space.
In chapter 10, ‘Kant’s Conception of Causal Necessity and Its Legacy’, Friedman examines Kant’s conception of force, its metaphysical basis and its place in the history of science. According to Friedman, Kant conceptualizes forces to be mathematically precise instantiations of the relational categories, whose behavior is inferred via Newtonian ‘deductions from the phenomena’. Such well-grounded forces then give rise to the causal necessity borne by genuine empirical laws of nature. Friedman subsequently provides an illustrative account of the development of the theories of electromagnetism and general relativity, which manifests these Kantian notions of force and causal necessity. The chapter concludes by elegantly weaving these considerations into the interstitial space of Friedman’s overarching research programme and motivating his dynamics-of-reason project (see Friedman Reference Friedman2001). Friedman explains that, although metaphysics and physics change in a complex, intertwined, and stepwise manner, the Kantian idea that there are a priori conditions and deductions from the phenomena that ground the robust causal necessity of empirical laws remains a consistent thread in post-Kantian thought (albeit the a priori becomes reconceptualized as relativized).
In chapter 11, ‘Metaphysical Foundations of Neoclassical Mechanics’, Marius Stan evaluates the prospects for grounding a comprehensive theory of mechanics on the foundation of MFNS. He first characterizes two approaches to Newton-Euler mechanics: one conceives of matter as point-like, the other as a deformable continuum. Stan argues that Kant’s metaphysical foundations of physics adequately support a mass-point mechanics, as long as one abandons Kant’s commitment to the infinite divisibility of matter. In contrast, to recover a deformable-continuum model from Kant’s metaphysics of nature would require major tweaks to the system, including comprehensive replacement of the Phoronomy and supplementation of the Mechanics with additional principles. Hence, in conclusion, Stan echoes and reinforces a thesis he has advanced elsewhere (see Stan Reference Stan2014): Kant ought to have stuck to his pre-Critical guns and conceived of matter as fundamentally point-like.
Breitenbach’s chapter 12, ‘Laws in Biology and the Unity of Nature’, is motivated by the difficulty of situating organisms in Kant’s system of nature. The problem derives from Kant’s claim that organisms must be conceived teleologically, not mechanically. Breitenbach argues that the teleological perspective on organisms is merely analogical and allows us to recognize the parts of an organism as belonging together and as collectively contributing to its hypothetical end (survival and reproduction). Yet, while the teleological perspective delimits the components of the organism as together contributing to its survival, these parts, themselves, can be studied mechanically. Such naturalistic consideration of organisms makes possible genuine biological laws of nature but does not eliminate the importance of the teleological perspective. Organisms, teleologically conceived, are a crucial analogue for the regulative idea of the unity of nature, as a whole.
The concluding chapter 13, Catherine Wilson’s ‘The Building Forces of Nature and Kant’s Teleology of the Living’, is a rich examination of Kant’s commitment to the existence of constitutive, active building forces that lie at the basis of various natural phenomena throughout his career. In his early, pre-Critical Universal Natural History (UNH below), Kant ascribed such an active building force to matter to explain the apparently directed history of the universe. Whereas commentators commonly think that Kant came to dismiss such building forces as merely regulative heuristics in CPJ, Wilson finds a lasting commitment to their constitutivity. Although Kant changes his thinking regarding the forces – they are blind mechanisms of nature in UNH but become conceivable only in terms of an analogy with intelligent action in CPJ – his commitment to the existence of building forces is unwavering, according to Wilson.
Overall, Massimi and Breitenbach’s volume is a superb resource for Kant scholars of all stripes. Its splendid chapters offer acute and profound insights on the vital topic of laws of nature in Kant’s thought.
