This article critically evaluates Jeffrey Koperski’s decretalism, which presents the laws of nature as divine decrees functioning as constraints rather than dynamic forces. Building on his work, we explore whether his model successfully avoids the implications of occasionalism, as he claims. By analysing his latest publications, we first reconstruct Koperski’s argument and then present three key objections. These include (1) issues related to scientific realism, (2) the principle of simplicity, and (3) the reduction of Koperski’s model to occasionalism. We argue that despite his attempts to distinguish his framework, Koperski’s model ultimately collapses into occasionalism due to the continuous divine sustenance required for natural processes. By engaging with recent developments in metaphysical and scientific debates, this article highlights the limitations of Koperski’s decretalism.

Occasionalism is often seen as a peculiarity of early modern philosophy. The idea that God is the sole source of efficient causation in the world strikes many as at best implausible. It was, however, a natural inference based on the seventeenth-century view that the laws of nature are simply God's decrees. The question here is whether such a view and its more recent descendants entail occasionalism. I argue that they do not, but showing why involves a new take on what exactly the laws of nature do.