This paper examines the origin, range and meaning of the Principle of Action and Reaction in Kant’s mechanics. On the received view, it is a version of Newton’s Third Law. I argue that Kant meant his principle as foundation for a Leibnizian mechanics. To find a ‘Newtonian’ law of action and reaction, we must look to Kant’s ‘dynamics,’ or theory of matter. I begin, in part I, by noting marked differences between Newton’s and Kant’s laws of action and reaction. I (...) argue that these are explainable by Kant’s allegiance to a Leibnizian mechanics. I show (in part II) that Leibniz too had a model of action and reaction, at odds with Newton’s. Then I reconstruct how Jakob Hermann and Christian Wolff received Leibniz’s model. I present (in Part III) Kant’s early law of action and reaction for mechanics. I show that he devised it so as to solve extant problems in the Hermann-Wolff account. I reconstruct Kant’s views on ‘mechanical’ action and reaction in the 1780s, and highlight strong continuities with his earlier, pre-Critical stance. I use these continuities, and Kant’s earlier engagement with post-Leibnizians, to explain the un-Newtonian features of his law of action and reaction. (shrink)

Philosophers after Leibniz used a technical idiom to classify and explain the nature of mental content. Substantive philosophical claims were formulated in terms of this vocabulary, including claims about the nature of mental representations, concepts, unconscious mental content, and consciousness. Despite its importance, the origin and development of this vocabulary is insufficiently well understood. More specifically, interpreters have failed to recognize the existence of two distinct and influential versions of the post-Leibnizian idiom. These competing formulations used the same technical terms (...) and taxonomic relations but assigned different connotations to those terms and employed different criteria for their application. This paper explains the two most influential versions of the post-Leibnizian idiom. (shrink)

Kant imposa au public philosophique la distinction entre sensations, intuitions et concepts. Bolzano reprit la terminologie, mais pas la substance de cette dernière. Cet article examine la critique astucieuse et détaillée qu’adresse Bolzano à Kant et présente les grandes lignes de sa théorie. Tandis que ses célèbres propositions « en soi » lui permirent de traiter avec précision des notions de conséquence, d’équivalence, d’analyticité, etc., en évitant le psychologisme logique si commun à l’époque, les intuitions font figure d’exception. Elles sont (...) introduites en rapport direct avec l’activité mentale : les intuitions sont des pensées — les épisodes qui représentent notre conscience empirique directe — et constituent en fait la porte étroite de la philosophie de l’esprit bolzanienne.Kant impressed on the philosophical public the distinctions between sensations, intuitions and concepts. Bolzano followed him in terminology, but not in substance. This essay deals with Bolzano’s astute and detailed critique of Kant, and then outlines his own theory. His famous propositions « in themselves », allowed him to discuss, with precision, the concepts of logical consequence, equivalence, analyticity, etc., and to escape from common logical psychologism. Intuitions are an exception. They are introduced with heavy reliance on mental activity and are thought — they are episodes representing our direct empirical awareness — and they indeed constitute the narrow door of Bolzano’s philosophy of mind. (shrink)

The chapter shows how Kant’s ethical thought as reflected in the lectures, responds to Baumgarten’s works on moral philosophy. I argue that Kant chose Baumgarten’s textbooks for his classes for genuinely philosophical reasons. The thorough discussion of Baumgarten’s views provided Kant with important clues for developing an original position, even if mostly in opposition to Baumgarten. I illustrate this complex role of Baumgarten with a few significant examples, that also highlight some original aspects of Baumgarten’s position in comparison to Wolff’s: (...) (1) Kant follows Baumgarten’s in focusing on obligation as the crucial issue in moral philosophy, but Kant regards Baumgarten’s account as not satisfying. (2) Baumgarten’s sharply theistic foundation of morality is rejected by Kant. (3) Kant rejects also several significant aspects of Baumgarten’s division of ethical duties, thereby revealing profound differences in their conceptions of morality. (shrink)