To be a master of one's own work is the only freedom worth having.
Sayers cuts against the romantic notion that freedom means escape from discipline—she's saying the opposite, that true liberty lives *inside* mastery, not outside it. The pianist who has spent ten thousand hours perfecting her craft possesses a freedom the dabbler never touches; she can make choices within her art that the untrained hand simply cannot execute. What makes this radical is the inversion: we usually think constraints limit us, but Sayers understood that deep knowledge of your medium is what actually sets you free to do something worth doing. A surgeon who knows her anatomy intimately can improvise with confidence in the operating room; an untrained person with a scalpel has only the illusion of freedom.