Full Idea
Prescriptivists hold that moral judgements commit the speaker to motivations and actions, but non-moral facts by themselves do not do this.
Gist of Idea
Prescriptivism implies a commitment, but descriptivism doesn't
Source
Richard M. Hare (Universal Prescriptivism [1991], p.459)
Book Reference
'A Companion to Ethics', ed/tr. Singer,Peter [Blackwell 1993], p.459
A Reaction
Surely hunger motivates to action? I suppose the key word is 'commit'. But lazy people are allowed to make moral judgements.