I argue that Kant acknowledges two models of spontaneous self-determination that rational beings like us are capable of. The first model involves absolute unconditional necessity and excludes any form of contingency. The second model involves a form of contingency which entails alternative possibilities for determining oneself. Given these two models, the principle that we are exclusively determined by natural causes poses a twofold threat for human agency. In one respect (in relation to the second model), it threatens us with the obliteration of contingency, or with the universality of hypothetical necessity. But in another respect (in relation to the first model), it threatens us (and our putative “laws”) with the obliteration of absolute necessity, or with the universality of contingency.