4 ideas
At the theatre Teste watches the audience rather than the stage. Back in his room he lies in pain and tries to hold the pain at a distance by describing it to himself as a figure he can measure, until he drifts toward sleep mid-sentence.
The narrator suggests that the most capable people may be entirely unknown, because publishing, seeking recognition, or producing work is a concession to other people's opinions and uses up the mind's energy. On this view, fame measures a mind's willingness to be seen, not its power.
Teste is said to have 'killed the puppet': he removed the automatic social persona of stock gestures, polite phrases, and borrowed opinions. What remains is a person who acts only from deliberate attention, so his outward life looks flat and anonymous while his inner work is intense.
Teste's governing question, 'What can a man do?', turns attention from what someone has achieved to the range of mental operations they can command. He practises and refines his own thought processes and discards whatever he cannot use, treating the mind as an instrument to train rather than a source of products.