The difficulty for Hume is to explain why we nonetheless typically experience pleasurable sentiments directed at instances of promise-keeping, despite the artificial foundation of the practice.
Aesthetic experience is a variety of free and unhindered activity of our representational capacity, and therefore produces pleasurable sentiments which are a primary constituent of happiness.
The central tenets of his metaphysics and psychology are that the human mind is essentially representational, so that desire and will as well as cognition are forms of representation, and that the ultimate source of all of our pleasurable sentiments is the unhindered activity of our capacity for representation.
On the contrary, in his view the causal relation between perfection in the object and the pleasurable sentiments of activity in the subject is precisely the sort of relation that gives rise to rules, although such rules will be fairly general rather than very specific.
I say insufferable; for the feeling was unrelieved by any of that half-pleasurable, because poetic, sentiment with which the mind usually receives even the sternest natural images of the desolate and terrible.
Though this appears ambiguous as between locating the beauty in the pleasure or in the impression or idea that causes it, Hume is soon talking about the 'sentiment of beauty,' where sentiment is, roughly, a pleasurable or painful response to impressions or ideas, though beauty is a matter of cultivated or delicate pleasures.
This claim is part of Hume's more general claim that our indirect passions (including our moral sentiments) are aroused and sustained only when the pleasurable or painful qualities concerned (e.g. the virtues and vices) stand in a durable or constant relation with the person who is their object (T, 2.1.6.7/292 3; DP, 2.11).
Pleasurable physical intimacies followed.
These scents were pleasurable.
Repetitive, but strangely pleasurable.
