The eighteenth-century German rationalist tradition is, broadly speaking, committed to (what I call) ‘the principle of rational cognition’: the grounded must be rationally cognizable from its sufficient ground. Whereas the prevailing view takes the fundamental challenge to rationalist paradise to stem from the principle of sufficient reason, I argue that it instead stems from this principle: How is it possible to rationally cognize anything at all from its ground? By investigating the opposing responses of two of Leibniz’s most influential immediate successors, Christian Wolff and Christian Crusius, we find no easy way to remain in rationalist paradise.

This article aims to highlight the extent to which Kant’s account of belief draws on the views of his contemporaries. Situating the non-evidentialist features of Crusius’ account of belief within his broader account, I argue that they include antecedents to both Kant’s distinction between pragmatic and moral belief and his conception of a postulate of pure practical reason. While moving us closer to Kant’s arguments for the first postulate, however, both Crusius’ and Meier’s arguments for the immortality of the soul fail to anticipate the most important aspect of their Kantian counterparts. Developing the non-evidentialist features of Basedow’s account of belief, I distinguish it from its Pascalian and Jamesian relatives and argue that it is the clearest antecedent to Kant’s arguments for the first and second postulates. Finally, I consider the development of Kant’s account of belief after the first Critique and discuss the broader implications of my analysis.

Kant criticizes the so-called ‘preformation’ hypothesis – a nativist account of the origin of the categories – at the end of the B-Deduction on the ground that it entails scepticism. I examine the historical context of Kant's criticism, and identify the targets as both Crusius and Leibniz. There are two claims argued for in this paper: first, that attending to the context of the opposition to certain forms of nativism affords a way of understanding Kant's commitment to the so-called ‘discursivity thesis’, by contrasting the possession conditions for the categories with those for innate ideas; secondly, it provides an insight with regard to Kant's understanding of the dialectic with scepticism. Kant's claim is that a certain explanatory lacuna that attaches to Humean empiricism can be seen to apply equally to any nativist theory. The lacuna concerns the explanation of the modal purport of a priori necessity, i.e. how it is that our consciousness can even distinguish contents that are represented as necessary features of objects.