5 ideas
Humans do not desire a particular pleasure but pleasure itself, and this desire has no limit in extent or duration. Every real pleasure is finite, so each one falls short. The mind responds by projecting pleasure into what it cannot yet grasp, which is why satisfaction always lives in anticipation and memory rather than possession.
In his 1820 notes on pleasure, Leopardi observes that a hedge, tree or tower that cuts off part of the horizon gives more pleasure than an open view. The eye cannot reach the limit, so the imagination supplies an unbounded space in its place. He writes the same about a song heard from the street at night as it fades into the distance.
Leopardi separates 'parole' (words) from 'termini' (terms). A term names its object exactly and nothing more, which suits science. A word carries a halo of accessory, indefinite ideas, which suits poetry.
Noia is not a trivial mood but the feeling of the emptiness left when no finite thing can fill an infinite capacity for desire. Being bored even with the whole world is therefore a sign of the mind's greatness, not of its poverty. Boredom is the purest form of the human condition, because it appears exactly when distraction and illusion are removed.
The ancients and children are happier and more capable of great action because they live inside illusions such as glory, love and patriotism. Reason and the progress of civilization dissolve these illusions without supplying anything to replace them, leaving truth together with paralysis. Over the years Leopardi comes to see nature itself as the source of human misery, a stepmother indifferent to the creatures it produces, rather than a kind mother betrayed by reason.