The problem of grounding natural modality in Kant's account of empirical laws of nature

One of the central problems of Kant's account of the empirical laws of nature is: What grounds their necessity? In this article I discuss the three most important lines of interpretation and suggest a novel version of one of them. While the first interpretation takes the transcendental principles as the only sources of the empirical laws' necessity, the second interpretation takes the systematicity of the laws to guarantee their necessity. It is shown that both views involve serious problems. The third interpretation, the “causal powers interpretation”, locates the source of the laws' necessity in the properties of natural objects. Although the second and third interpretations seem incompatible, I analyse why Kant held both views and I argue that they can be reconciled, because the metaphysical grounding project of the laws' necessity is accounted for by Kant's causal powers account, while his best system account explains our epistemic access to the empirical laws. If, however, causal powers are supposed to fulfil the grounding function for the laws' natural modality, then I suggest that a novel reading of the causal powers interpretation should be formulated along the lines of a genuine dispositionalist conception of the laws of nature.