 The Categorical Imperative is not the only principle of practical reason that Kant endorses. At nearly the same level of generality is the principle underlying all “hypothetical imperatives.” (See  Kant’s moral philosophy, §4.)  Imperatives of skill and prudence rely on the principle: “Whoever wills the end also wills (insofar as reason has decisive influence on his actions) the indispensable necessary means to it that are within his power” (4:417f; cf.  5:19f[17]).  Following Hume, many philosophers hold that practical reasoning is essentially instrumental. They therefore see all practical demands as ultimately hypothetical, that is, conditional upon our having particular ends or inclinations (cf.  Kant and Hume on morality,  §3). Kant, however, sees the principle of hypothetical imperatives as subordinate to the Categorical Imperative (cf. Korsgaard 1997). Reason can also be the source of unconditional demands, that is, demands that do not presuppose any particular ends or inclinations. Kant’s claim can be put even more strongly: reason is the only source of unconditional demands that human beings can ever have access to.