Full Idea
What rule of actions can be formed, without relation to some end proposed? Or what end can be proposed, without presupposing instincts, desires, affections, or a moral sense, it will not be easy to explain.
Gist of Idea
You can't form moral rules without an end, which needs feelings and a moral sense
Source
Francis Hutcheson (Treatise 4: The Moral Sense [1728], §IV)
Book Reference
'British Moralists 1650-1800 Vol. 1', ed/tr. Raphael,D.D. [Hackett 1991], p.320
A Reaction
We have no reason to think that 'instincts, desires and affections' will give us the remotest guidance on how to behave morally well (though we would expect them to aid our survival). How could a moral sense give a reason, without spotting a rule?