How we cite our quotes: Section.Part (if applicable).Paragraph
Quote #7
While we are ignorant whether a man were aggressor or not, how can we determine whether the person who killed him be criminal or innocent? But after every circumstance, every relation is known, the understanding has no further room to operate […] The approbation or blame which then ensues, cannot be the work of the judgement, but of the heart. (AI.11)
This quote highlights why we need start out by getting the facts. In any criminal case, it's important to try to find out exactly what went down rather than be ruled by our emotions. But once we've done that, there's no more to understand: intellectual inquiry hits a brick wall and our sense of humanity comes to the rescue.
Quote #8
Ask a man why he uses exercise; he will answer, because he desires to keep his health. If you then enquire, why he desires health, he will readily reply, because sickness is painful. If you push your enquiries farther, and desire a reason why he hates pain, it is impossible he can ever give any. This is an ultimate end, and is never referred to any other object. (AI.18)
Hume takes a moment here to show how reason can only go so far. If we ask someone why they exercise and they tell us it's for health reasons, that's our question answered. But if we start asking why they want to be healthy and why they hate pain, they're gonna struggle to answer (and get pretty cheesed off). C'mon, you don't have to be Einstein to see that hating pain is a natural response—not an intellectual thing.
Quote #9
Thus the distinct boundaries and offices of reason and of taste are easily ascertained […] The one discovers objects as they really stand in nature, without addition and diminution: the other has a productive faculty, and gilding or staining all natural objects with the colours, borrowed from internal sentiment, raises in a manner a new creation. (AI.21)
Reason and taste work in different ways, with reason giving us the lowdown on what's true/false and taste guiding our overall moral outlook. Reason focuses on things as they are but taste brings something new to the table. Hume conjures up the image of a paint brush sweeping across the landscape, adding color to the world. Like a finished artwork, sentiment builds on reason to create something new.