This collection addresses some of the injustices associated with modern European politics. It begins by addressing the evils of conquest, of Christian oppression and the crusades. Then follows a series of poems denouncing the human debasement and the immorality of slavery. Nationalism is decried. Some European defenders of peace and justice are cited, including Bartolomé de Las Casas, Fénelon, and Montesquieu. Their contribution to a more just history of humankind, described here as a natural history of humankind, is acknowledged. Prominent historical figures such as Vasco de Gama, Afonso de Albuquerque, Hernán Cortés, and Francisco Pizarro are condemned for their acts of conquest. A model of perpetual peace based on universal fairness, humaneness, and active reason is put forward as an alternative to that offered by Kant. On this basis, several practical dispositions to peace are given. The damaging effects of a history based on illusions of progress are described, and, with James Burnett, Lord of Monboddo, as an example, a non-teleological history is promoted. The collection ends with an appeal to true Christianity, which is seen as dictating the good of all humanity.

Matthew Boyle relates Kant’s account of cognition to Aristotle’s hylomorphic theory of substance. On Aristotle’s view, the form of a substance is the ground of its existence. To know this form is to know those of its properties without which it cannot exist. These characterize the substance as it is in itself. Such knowledge of form amounts to knowledge of a thing in itself, and the view that such knowledge is possible for us might be called formal realism. Kant thinks that this requires a type of mind human beings do not have: a non-discursive intellect. Boyle argues that Kant transposes Aristotle’s hylomorphic framework from a formal-realist to a formal-idealist register, and so “internalizes” the form-matter contrast. Instead of speaking of forms of being qua being Kant speaks of forms of objects insofar as they are knowable by a finite intellect. For Kant, just as for Aristotle, the form of a thing is its essence (and thereby the ground of its intelligibility). But for things whose form is ideal – appearances – knowledge of form cannot amount to knowledge of the ground of their existence. It can only amount to knowledge of the ground of their knowability.

“The Poet” is what Adorno calls a “carpet essay,” which weaves its announced topics of the poet and poetry into a host of other subjects: character and expression; reception and abandonment; beauty and love; the present, new, and near; the Neoplatonic One or “whole”; and a fundamental “flowing” or “metamorphosis.” Chapter 8 focuses on Emerson’s romantic and proto-existentialist pronouncement that “the man is only half himself, the other half is his expression”; his theory that language “is fossil poetry”; and the proto-pragmatic picture of language in his statement that “all language is vehicular and transitive, and is good, as ferries and horses are, for conveyance, not as farms and houses are, for homestead.” Other topics treated are the place of what Kant calls “unbounded” ideas in Emerson’s account of poetry, thinking as a mixture of reception and activity, and the connections and differences of “Experience” and “The Poet.”

This chapter lays out the ways in which Hans Christian Ørsted (1777–1851) influenced the development of the concept of thought experiment. Ernst Mach (1838–1916) is currently more often credited with laying the foundations of contemporary views, and he is sometimes thought to have been little (if at all) influenced by Ørsted. Against these standard accounts, I will show that Ørsted’s and Mach’s descriptions have key features in common. Both thinkers hold that thought experiments: (1) are a method of variation, (2) require the experimenter’s free activity, and (3) are useful in educational contexts for guiding students to arrive at certain conclusions on their own (i.e., to genuinely appropriate new concepts). The process of variation is guided by the search for invariants, some of which do not directly appear in experience. Since it is important that teachers and students be able to bring the same ideal objects to mind, thought experiments play a key role for both Ørsted and Mach in math education. While Ørsted’s emphasis on the role of thought experiments in math has been proposed as a reason why his descriptions are not relevant for contemporary use of thought experiments, I will show how their role in mathematical thinking – stemming from Kant’s descriptions of the method of construction in geometry – are part of a wider account of thought experiments that encompasses their role in the sciences and also philosophy.

This chapter develops and analyzes how thought experiments connect thinking with actuality. Superficially, imaginary constructions are mere possibilities that diverge from actuality. However, Kierkegaard also characterizes thought experiments as a kind of experience, providing concrete, fulfilling content for an otherwise empty concept – that is, providing what Kant calls a “synthesis” between thought and experience. Two Ages shows how the work of synthesis can begin from observations and move toward understanding or from understanding toward fulfillment in experience. In Works of Love, I propose, we find material for a basic taxonomy of thought experiments that distinguishes them by whether the thought experiment offers cognition of (a) objects or (b) concepts and whether it (a) proceeds from existing concepts or (b) guides the reader in gaining new ones. This taxonomy mirrors Kant’s distinctions between constitutive and regulative concepts and determining and reflecting judgments. It also anticipates the proposals of recent rationalist accounts of intuition that thought experiments provide nonsensory presentations.

Kant thinks it is possible to achieve nonperceptual cognition in three ways: (1) through practical action, (2) by analogy, and (3) through construction. The type of cognition available depends on the kind of object or concept being cognized. The fact that cognition of nonperceptual objects is possible in some cases opens the way for thought experiments to provide cognition in ways that go beyond providing fictional examples and exemplifications. In this chapter, I describe these other possibilities for cognition and show how they are at work in different kinds of thought experiments in philosophy.

The conclusion outlines key points in the book. On a Kantian-Kierkegaardian account, thought experiments lead to presentations that justify calling a thought experiment an experience, though not an empirical or sensory one. Without a sensible object, we can nevertheless have givenness, or presence, but not existence. Cognition, for that reason, is not necessarily truthful: although object-directed, cognition on its own does not justify belief in any particular object’s existence. My conclusion that thought experiments provide cognition rather than knowledge echoes Michael Stuart’s claim that thought experiments increase understanding. Cognition is a common basis for knowledge in Kant, but it is not the same thing as knowledge. The conclusion also draws implications for how we understand faith (religious belief) in Kierkegaard and how thought experiments make sense of the complexity of reality.

Rationalist accounts of thought experiment in epistemology offer an alternative to the more predominantly empiricist approaches in philosophy of science. In this chapter, I will pose a Kantian critique of recent rationalist accounts of intellectual intuition. Some epistemologists have recently argued that intellectual intuitions can provide prima facie justification for judgments. In this chapter, I highlight some promising elements of recent rationalist accounts, especially the proposal that there can be nonsensory presentations analogous to empirical perceptions. If they are right, then thought experiments can provide new experiential content even without empirical confirmation. However, I also draw attention to Kant’s objections to the possibility of purely intellectual intuitions.

In philosophy of science, Mach’s account of thought experiments is more often described as relevant for contemporary usage than Ørsted’s. In this chapter, I survey recent Kantian accounts of thought experiment, arguing that the leading views inspired by Kant in philosophy of science remain broadly empiricist. This tendency may be due to their focus primarily on the role of thought experiments in the sciences. In later chapters, I will argue – against recent Kantian views – that Kant understood cognition more broadly to include not only sensory perception but also mathematical construction. Acknowledging that cognition does not always require empirical fulfillment opens new ways of understanding how thought experiments work in philosophy, which may rightly differ from their use in the sciences.

The purpose of this chapter is to analyze Kant’s approach to writing philosophical texts, as such. By his own admission, Kant struggled with making his texts clear. He viewed this problem as not only technical, but as properly philosophical. It will be demonstrated that Kant carefully analyzed different types of linguistic clarity in his Lectures on Logic, that he fully recognized the difficulty of achieving them in practice, and that he nevertheless granted his readers the ‘right’ to ‘legitimately demand’ a certain level of clarity in principle. It will then be examined how and why Kant deployed various forms of metaphorical language to meet this challenge – a strategy which has, in turn, opened promising avenues for scholars interpreting his works. An analysis of the Critique of Pure Reason will illustrate how Kant ingeniously exploited metaphors to combine “discursive (logical) clarity” with “intuitive (aesthetic) clarity,” aiming for an ideal he termed “lucidity [Helligkeit].” In particular, the discursive structure of the Critique is represented here through an analogical model based on Kant’s vividly metaphorical description of moral character formation in the Anthropology.

According to Cassirer, Kant’s Critique achieves a new look at the dichotomy between “consciousness and actuality, the I-world and the world of things.” Indeed, the Critique of Reason “sets out a new positive concept of subjectivity and objectivity […]. The world of the subject and objects no longer stands as two opposing halves of one absolute being; rather, being constitutes one and the same realm of spiritual functions through which we obtain the content of both […]. This abstract result was introduced by Humboldt, through the mediation of language in the concrete consideration of spiritual life.” Humboldt seizes on a possibility indicated in the first Critique and builds his philosophy of language as a mediation of the subjective and the objective. This is an original way of understanding Humboldt. Understanding Humboldt’s philosophy of language in light of Kant will constitutes the first part of this chapter. In the second part, I spell out what this Humboldtian interpretation of language means for Cassirer. Cassirer sees Humboldt as a precursor to his own work on language. My chapter sheds light on a possibility regarding language indicated by Kant, worked out by Humboldt, and then exploited by Cassirer.

Much useful attention has been focused on Kant’s views of the relation between language and thought, as well as the relation between grammar and logic, asking especially whether Kant thinks that the activity of thinking depends on or involves linguistic phenomena – that is, whether Kant upholds the linguisticality of thinking. Here I focus instead on the relation between language and ‘the senses,’ and sensibility more generally. After sketching what such an interpretation might look like and providing some initial textual grounds for its support, I then turn to some of the details of accounts of the linguisticality of sensibility among Kant’s historical predecessors (Berkeley, Baumgarten), to help round out and deepen our understanding of what sorts of commitments might go into such a view, before returning to the closer examination of Kant’s own texts. I conclude that Kant does in fact maintain a fairly well-developed version of the linguisticality interpretation of sensibility, and raise some questions about what this means for the linguisticality of thought itself.

Kant is often cited by contemporary expressivists as an early proponent of expressivism. But that association remains controversial. In this chapter, I consider whether Kant is best read as an expressivist, focusing on his account of practical thought and language. In doing so, I present a variety of reasons for thinking that Kant’s views are similar in central respects to contemporary forms of expressivism. But I also argue that there are good reasons for the Kantian to resist any such assimilation – reasons for them to think that Kant’s view is not a form of expressivism, but something better than it.