 Arnold Geulincx’s most distinctive contribution to the development of occasionalism comes in the form of a causal principle that puts an epistemic restriction on the exercise of genuine causality (see Nadler 1999, 268). In his Metaphysica vera, Geulincx states that “it is impossible to bring about something when one does not know how it is brought about … you are not the cause of that which you do not know how to bring about (impossibile est, ut is faciat, qui nescit quomodo fiat … quod nescis quomodo fiat, id non facis)” (MV 150–1). If restricted to the causality of rational, intentional agents, the principle seems to have some intuitive appeal. But Geulincx, interestingly enough, does not restrict the principle in this way. Rather, he takes it to be universally applicable, even to bodily causes, which has raised questions about the plausibility of this overall argument. Malebranche appears to be taking up a version of this principle, which we will discuss later in the section on the “no representation” argument.