4 ideas
Rasselas, a prince of Abyssinia, lives in a mountain-walled valley where every want is supplied, yet he grows restless precisely because he has nothing left to desire. After months of planning, and after a failed attempt at flight by a mechanical artist's wings, he tunnels out with his sister Nekayah, her attendant Pekuah, and the poet-sage Imlac to make a 'choice of life' in the world outside.
A human being cannot be happy when all needs are met, because the mind feeds on hope and pursuit rather than on possession. Once nothing remains to strive for, contentment turns into tedium, so a steady supply of unsatisfied wants is a condition of felt well-being, not an obstacle to it.
The travellers test each candidate way of living in turn: the pleasure-seekers, the Stoic lecturer, the pastoral shepherds, the rich man, the hermit, private family life, and high office. Each looks happy from outside, but close inspection shows its own anxiety or disappointment, so the search ends in the recognition that no single 'choice of life' secures lasting happiness.
A learned astronomer, after years of solitary study, becomes convinced that he governs the weather and the seasons and bears responsibility for the world's rain and sun. Johnson uses him to show that imagination left unchecked in isolation gradually overpowers reason, and he recovers his sanity only when he is drawn back into ordinary company and conversation.