> But this "naturalistic" solution is exposed to grave difficulties: it seems to be impossible to give an adequate account of human ends by conceiving of them merely as posited by desires or impulses.

The fact that to somebody something "seems" impossible is a moot point without argumentation. Unless that (argumentation) is given elsewhere, this is yet another cavalier dismissal of something based on personal prejudices, which has been so dear to different authors in the history of ideas.