 There is, of course, an important difference between examples like those of the prince and the king, and example of an action to which one is moved by efficacious grace. In examples of the former sort, the action occurs only with very great, but not absolute, certainty, whereas in the case of efficacious grace, the action follows with absolute certainty upon God’s intention that it take place. This difference may seem to damage Arnauld’s case: One can plausibly say that it was within the power of the prince, for example, not to will to satisfy his lust, precisely because it was not absolutely certain that, in the given circumstances, he would do so. But no similar claim can be made about the person whom God moves, by efficacious grace, to elicit a meritorious volition. Yet Arnauld insists that in the latter case also, it is within the power of the person not to elicit the volition. It is at this point that Arnauld’s views about the mysteriousness of divine causality come into play. Our inability to understand how God moves a person to a meritorious volition, while leaving it within the person’s power not to elicit the volition, thus moving the person to will in a self-determining way, is not, in Arnauld’s view, surprising, for we are unable, in general, to understand how God produces effects outside of Himself.