Sextus Empiricus reports arguments against voice and mental movements as truth bearers. I argue that some of these arguments are Stoic and justify the Stoic view that truth and falsity belong to a third item, the lekton – the incorporeal signification of linguistic utterances. The argument against voice is that only significant voice can be true or false, but those who do not speak our language can hear our voice without understanding the signification. So truth cannot lie in the voice, but in its signification, by grasping which we recognise the truth or falsity of what someone has said. Mental movements are private to each individual and others cannot even know for sure what another person’s thoughts are, let alone whether they are true or false. There would be no way to establish an agreement on what is true. These arguments contain the desiderata that a truth bearer must be publicly accessible and able to be known. These desiderata are fulfilled by lekta as they are signified by linguistic utterances but not identical to mental movements. In this way, I propose to answer the question of why the Stoic truth bearers are lekta and not something else.

In Kants Augen unterscheidet sich das sogenannte infinite Urteil „Steine sind unsterblich“ nicht nur strukturell, sondern auch inhaltlich vom verneinenden Urteil „Steine sind nicht sterblich“, weil es mehr besagt, als dass es Steinen an Sterblichkeit mangelt. Laut Strobach besteht dieses Mehr darin, dass ein Objekt, das unter einen negierten Begriff fällt, unter den zugehörigen nichtnegierten Begriff fallen könnte. Diese Deutung ist allerdings mehreren Problemen ausgesetzt. So stimmt sie nicht mit Kants Diktum überein, dass die Kategorie Limitation aus der Verbindung der Kategorien Negation und Realität entspringt. Ich stelle deshalb eine Interpretation vor, die sich aus der „traditionellen Begriffstheorie“ herausziehen lässt, wie sie Kant zugeschrieben wurde. Nach dieser Theorie sind Begriffe in Gattung-Art-Hierarchien organisiert, die durch „logische Einteilung“ entstehen. Dementsprechend gehören die Dinge, die unter einen Begriff und seine Negation fallen, zu einer gemeinsamen Gattung, die beide Begriffe in ihrer Anwendung einschränkt. Abschließend wird dem Einwand begegnet, dass diese Interpretation – anders als die von Strobach – keine allgemeine Regel für die Ermittlung der einschränkenden Gattung bietet. Tatsächlich stimmt dies mit unserer Verwendung negierter Begriffe überein: Wer einen Begriff und die Kopulanegation beherrscht, beherrscht damit noch nicht den zugehörigen negierten Begriff, weil dafür eben auch die relevante Gattung bekannt sein muss.

Kant’s pre-critical possibility proof for the existence of God, which he develops in detail in the Beweisgrund from 1763/64, is often thought to have Spinozistic implications. One key reason for this is that Kant’s reasoning in the Beweisgrund appears to entail that God is extended or spatial. Kant argues that God exemplifies all fundamental or primitive predicates. Since he also treats extension as such a fundamental predicate, it straightforwardly seems to follow that God is extended. This paper argues that Kant’s argument in the Beweisgrund does not, in fact, lead to this Spinozistic conclusion. In other writings from the same period Kant distinguishes between concepts that are fundamental for us and concepts that are fundamental in themselves, and he even applies this distinction to the concepts of space and time. With this distinction in hand, Kant is equipped with the resources to block the Spinozistic conclusion that God is extended: he can accept that extension is a fundamental concept for us while simultaneously rejecting that extension is a concept fundamental in itself. Thus, extension need not be a predicate that is exemplified by God, and the Spinozistic threat can be averted.

Kant’s rejection of the Principle of the Identity of Indiscernibles is both explicit in his own writings and unanimously acknowledged by commentators. By contrast, Kant’s stance on the Principle of the Indiscernibility of Identicals, i.e. Leibniz’s Law, surfaces only sparsely in his writings and has escaped direct attention in Kant scholarship. Leibniz’s Law roughly states that if a and b are identical, then b has every property a has, and vice versa. In my talk I will present a comprehensive study of the scant writings pertinent to a reconstruction of Kant’s position. Prima facie these passages suggest two opposing lines of interpretation. According to the first, Kant approves of Leibniz's Law (Approval Reading). According to the second, Kant rejects Leibniz's Law (Rejection Reading). Yet the opposition of the Approval and the Rejection Reading is, as I will show, merely apparently exhaustive — an Ecumenical Reading is available: I will argue that, while Kant ,approves' of the truth of the proposition expressed by Leibniz's Law, he ,rejects' Leibniz's Law as a genuine principle.

How is inquiry possible? Since Meno’s paradox, it has seemed that inquiry requires some intuitive grasp of ultimate explanations. Yet a core tenet of Kant’s philosophy is that reason is discursive, i.e. conceptual. While some scholars argue that discursivity accounts for the demand for explanation, I contend that this thesis cannot explain the possibility of inquiry—for it fails to generate its goals. To address this gap, I propose an alternative approach. Rather than collapsing discursivity and the demand for explanation, I isolate them as distinct aspects of reason, which allows us to understand how they interact in generating goals of inquiry. First, I argue that the logical use of reason, tied to discursivity, fails to guide inquiry toward explanations. Second, I propose that the real use of reason, which generates concepts of totalities of grounds, is the source of the demand for explanation. Finally, I introduce two models for understanding such totalities—ontological and representational—and argue that the latter enables us to treat totalities as goals, rather than given realities—thereby making inquiry purposive. This provides a Kantian solution to Meno’s paradox by reconceptualizing inquiry as an active process that generates knowledge through the approximation of explanations.

In the Doctrine of Virtue, Kant introduces gratitude as an imperfect duty to others. Kant’s characterisation of the duty of gratitude is, however, not easily reconciled with the idea that being thankful is an imperfect duty, i.e., a duty which allows agents to find their own distinctive ways in which to realise the demands of the moral law. Rather, Kant appears to suggest that recipients of beneficent gifts are required to reciprocate favours as if they had to make up for a debt, thereby bringing gratitude close to the fulfilment of a perfect duty. In this talk, I aim to challenge the view that Kant wants us to understand gratitude as a duty to repay a debt. To that end, I propose a novel reading which helps us make sense of gratitude as an imperfect duty. On the Opportunity Reading, as I shall call it, the duty of gratitude consists in taking acts of benevolence one has received as opportunities to become oneself a benefactor to others. In this regard, the duty of gratitude turns out to be a version of the duty of beneficence and thus a genuine imperfect duty to make the well-being of others one’s end.