Those who knew him in childhood remembered a lively, outgoing personality. Yet as time went by, while his music retained a boyish sparkle and vigour, he personally became more withdrawn and introspective as he dedicated his energies exclusively to composing and writing learned treatises. As one close friend put it: “His heart and soul were in the harpsichord; once he had shut its lid, there was no one home.”
What is the meaning of 'there was no one home'? Shutting his mouth? secluding himself at the corner? retiring into his inner shell? No social contact?