Lorenzo Spagnesi

Scientific models often contain assumptions known not to be true. Despite being false representations, models provide us with a key understanding of phenomena. What is more, the falsehoods that figure in models are in many cases central to them, and there is no available alternative to their use. If falsehoods play such an irreplaceable role in our understanding of phenomena, it would seem that truth is not a key concern of scientific modeling. In this paper, I assess the prospects and challenges of reconciling truth and understanding in scientific modeling. More specifically, I review a thesis recently emerging in the literature, what I shall call the Derivation Thesis (DT), according to which we use models to derive true information. First, I examine different versions of the thesis and develop what I take to be its most promising formulation (what I call the generalized DT). Second, I discuss a serious challenge to the generalized DT. I consider a thought experiment in which an unreliable astrological model gives true explanations by fluke. This scenario challenges the idea that models can provide genuine understanding by generating truths. In response, I argue that genuine scientific models also fulfill a specific normative role that epistemically lucky models lack (what I call the normative generalized DT). I test this hypothesis by analysing how the Ideal Gas Law advances scientific understanding of real gases.

What can we know? We know many things about the world around us: whether it is raining outside, the result of last night’s game, or how vaccines work. But we also want to know more. For example, we may want to know the ultimate origin of the universe, whether God exists, or whether there are such things as souls. Philosophers have long asked this type of questions — questions that concern a kind of knowledge that goes beyond our experience. A wide range of answers (often contradicting each other) have been endlessly debated. Dissatisfied with this state of inquiry, Kant proposes a revolution in philosophy, which does not consist in devising new answers to these questions, but rather in analyzing our own capacity for knowledge. Such an analysis aims to shed light on the limits of our cognitive faculties and to reveal their true potential. In this article, we will see how Kant’s philosophy offers a revolutionary approach to our deep thirst for knowledge.

Despite recent essentialist approaches to Kant’s laws of nature, it is unclear whether Kant’s critical philosophy is compatible with core tenets of essentialism. In this paper, I first reconstruct Kant’s position by identifying the key metaphysical and epistemological features of his notion of ‘nature’ or ‘essence’. Two theses about natures can be found in the literature, namely that they are noumenal in character (_noumenal thesis_) and that they guide scientific investigation as regulative ideas of reason (_regulative thesis_). I argue that Kant’s notion of nature does not entail the noumenal thesis and, based on his model of causal explanation, I propose a novel, _phenomenal thesis_, that allows for a better understanding of the function of natures as regulative ideas. In the last part of the paper, I show that Kant’s ‘essentialism’ is a genuine form of essentialism committed to _de re_ modality, although it differs in several respects from major contemporary essentialist accounts. I conclude by suggesting that Kant’s essentialism (if appropriately updated) can be relevant to the contemporary debate, which has so far been dominated by Humean and Aristotelian proposals.

In this paper, I offer a systematic account of Kant’s view on ‘phenomenal substance’. Several studies have recently analysed Kant’s notion of substance. However, I submit that more needs to be said about how this notion is reconceptualized within the critical framework to vindicate a genuine and legitimate sense of substance in the phenomenal realm. More specifically, I show that Kant’s transcendental idealism does not commit him to a rejection of substantiality in phenomena. Rather, Kant isolates a general notion of substance (as ultimate subject) and argues that (i) the relationality of phenomena is compatible with this notion; and that (ii) matter and all its parts are the ultimate subjects of everything existing in space (as what is independently movable in space). I suggest that vindicating a genuine and legitimate notion of phenomenal substance has far-ranging consequences for the interpretation of Kant’s empirical realism.

In this paper, I argue that Kant’s phenomena, though consisting in a network of relations, can nonetheless be efficacious and give rise to real changes. I begin by examining why intrinsic properties seem necessary to account for real changes. I then clarify some key concepts in the debate on relational properties and identify Kant’s spatial sense of relationality. This spatial sense, I argue, provides the basis for identifying a subset of empirical properties as 'comparatively intrinsic', preserving intrinsicness while being fully relational. I conclude by showing that real changes can occur in the phenomenal realm when they concern comparatively intrinsic properties of objects.

This article analyses a sceptical challenge resulting from metaphysical approaches to the problem of the necessity of empirical laws of nature in Kant’s critical philosophy (what I shall call ‘essentialist’ readings). I argue that this challenge may jeopardize the purpose of empirical enquiry (and therefore the plausibility of essentialist readings), but that Kant has internal resources to address it in the Dialectic of the Critique of Pure Reason. I show that reading this problem through the lens of the Dialectic allows us to reconcile the metaphysical question of necessitation of laws with a robust sense of empirical cognition.

Scientific models typically contain idealizations, or assumptions that are known not to be true. Philosophers have long questioned the nature of idealizations: Are they heuristic tools that will be abandoned? Or rather fictional representations of reality? And how can we reconcile them with realism about knowledge of nature? Immanuel Kant developed an account of scientific investigation that can inspire a new approach to the contemporary debate. Kant argued that scientific investigation is possible only if guided by ideal assumptions—what he calls “regulative ideas”. These ideas are not true of objects of nature, and yet they are not heuristic tools or fictional represen- tations. They are necessary rules governing the construction and assessment of scientific explanations. In this paper, I suggest that some idealizations can be interpreted as having necessary regulative value and as being compatible with scientific realism. I first analyze the puzzle of the nature of idealization and present the main approaches to this topic in the literature. Second, I reconsider the puzzle vis-a-vis a restricted, Kantian definition of idealization and a novel characterization of the relation between idealization and truth. Finally, I discuss in detail an example of idealization (the Hardy-Weinberg equilibrium) along the suggested Kantian lines.

This paper attempts a reconstruction of reason’s contribution to empirical truth in connection with Kant’s definition of truth as the agreement of cognition with its object. I argue that Kant’s treatment of truth in the Transcendental Analytic gets completed in the Appendix to the Transcendental Dialectic with an often neglected but compelling argument (what I shall call the Variety Argument). This argument postulates such a variety in the appearances as to undermine any attempt at formulating empirical truths. Crucially, I argue that this variety does not depict an extreme-case scenario, but our own epistemic situation without reason. Reason completes Kant’s theory of truth by allowing the understanding (i.) to form empirical concepts and (ii.) approximate to empirical truth.

This paper aims to show how Kant’s account of theoretical reason can inform the contemporary debate over unity and pluralism of science. Although the unity of science thesis has been severely criticized in recent decades, I argue that pluralism as the sole epistemic principle guiding science is both too strong and too weak a principle. It is too strong because it does not account for the process of theory unification in science. It is too weak because it does not answer the question of how science ought to be done. I then look at a promising ‘perspectival’ (i.e., epistemically situated) approach to the problem Kant presents in the Appendix to the Transcendental Dialectic. I argue that the logical principles of systematicity (homogeneity, specification, continuity) form a ‘perspectival space’ within which scientists can pursue both unity and disunity of cognition. Finally, I suggest that the existing conflict between pluralism and unity ultimately resides in a metaphysical characterization of unity that does not correctly capture its epistemic significance in science. Looking at Kant’s ‘perspectivism’ not only allows us to resolve this apparent antinomy, but also to rethink unity and pluralism as mutually inclusive regulative principles.

What makes scientific knowledge possible? The philosopher Immanuel Kant in his magnum opus, the Critique of Pure Reason, had a fascinating and puzzling answer to this question. Scientific knowledge, for Kant, is made possible by the faculty of reason and its demand for systematic unity. In other words, cognition about empirical objects can aspire to be scientific only if it is rationally embedded within or transformed into a system. But how can such system form once we take into account the perspectival nature of knowledge, i.e., its being situated in individual human cognitive faculties? My PhD thesis has a two-pronged objective: to reconstruct the complexity of the notion of systematicity in Kant’s Critique of Pure Reason; and to defend its plausibility in contemporary debates on the unity or plurality of scientific knowledge. As far as is concerned, Kant’s position is far from being clearly understood in the literature. Despite a renewed interest in Kant’s notion of systematicity in recent decades, existing contributions fail to offer a satisfactory account of it. The aim of my thesis is to provide a unified reading of reason’s systematicity as an essential feature of Kant’s analysis of the sources of cognition. In particular, I defend a novel account of theoretical reason the aims to support the following claims: systematicity is grounded in a legitimate use of reason’s ideas as prescriptive rules for empirical investigation; it is necessary to make empirical cognition possible and generate scientific hypotheses; and it gives us fundamental insights into Kant’s ‘empirical realism’ and his understanding of the role of metaphysics in science. With regard to, I show that Kant’s account of theoretical reason has much more to offer than generally acknowledged. In particular, I present it as providing a reconciling solution to the conflict between unity and pluralism in contemporary philosophy of science. Drawing inspiration from Kant’s ‘perspectivism,’ I argue that unity and pluralism are to be thought as mutually inclusive principles of scientific knowledge.

The aim of this paper is to propose a novel reading of the critical legitimacy of the regulative use of reason in the Transcendental Dialectic of Kant's Critique of Pure Reason. After introducing some key terminology of the Dialectic, I analyse the shortcomings of two influential accounts of the regulative use of reason and identify their common problem in their commitment to the descriptivity of the ideas of reason. I then offer my rule‐based account of the regulative use of reason by clarifying how Kant transforms reason's metaphysical inclinations into prescriptive rules of bottom‐up empirical research. Finally, I explain why such interpretation of reason is metaphysically innocent and thereby a promising approach to understand its role in Kant's scientific project.

This article aims to justify the positive role in the empirical investigation of nature that Kant attributes to the idea of God in the Critique of Pure Reason. In particular, I propose to read the Transcendental Ideal section and the Appendix to the Transcendental Dialectic together to see whether they can reciprocally illuminate each other. I argue that it is only by looking at the transcendental deduction of the ideas of reason and the resulting analogical conception of God that a fully legitimate positive use of the idea of God can be vindicated.