 By contrast with the maxim of the lying promise, we can easily conceive of adopting a maxim of refusing to develop any of our talents in a world in which that maxim is a universal law of nature. It would undoubtedly be a world more primitive than our own, but pursuing such a policy is still conceivable in it. However, it is not, Kant argues, possible to rationally will this maxim in such a world. The argument for why this is so, however, is not obvious, and some of Kant’s thinking seems hardly convincing: Insofar as we are rational, he says, we already necessarily will that all of our talents and abilities be developed. Hence, although I can conceive of a talentless world, I cannot rationally will that it come about, given that I already will, insofar as I am rational, that I develop all of my own. Yet, given limitations on our time, energy and interest, it is difficult to see how full rationality requires us to aim to fully develop literally all of our talents. Indeed, it seems to require much less, a judicious picking and choosing among one’s abilities. Further, all that is required to show that I cannot will a talentless world is that, insofar as I am rational, I necessarily will that some talents in me be developed, not the dubious claim that I rationally will that they all be developed. Moreover, suppose rationality did require me to aim at developing all of my talents. Then, there seems to be no need to go further in the CI procedure to show that refusing to develop talents is immoral. Given that, insofar as we are rational, we must will to develop capacities, it is by this very fact irrational not to do so.