As seen from the economic point of view, leisure, considered as an employment, is closely allied in kind with the life of exploit; and the achievements which characterise a life of leisure, and which remain as its decorous criteria, have much in common with the trophies of exploit. But leisure in the narrower sense, as distinct from exploit and from any ostensibly productive employment of effort on objects which are of no intrinsic use, does not commonly leave a material product. The criteria of a past performance of leisure therefore commonly take the form of "immaterial" goods. Such immaterial evidences of past leisure are quasi-scholarly or quasi-artistic accomplishments and a knowledge of processes and incidents which do not conduce directly to the furtherance of human life. So, for instance, in our time there is the knowledge of the dead languages and the occult sciences; of correct spelling; of syntax and prosody; of the various forms of domestic music and other household art; of the latest properties o dress, furniture, and equipage; of games, sports, and fancy-bred animals, such as dogs and race-horses. In all these branches of knowledge the initial motive from which their acquisition proceeded at the outset, and through which they first came into vogue, may have been something quite different from the wish to show that one's time had not been spent in industrial employment; but unless these accomplishments had approved themselves as serviceable evidence of an unproductive expenditure of time, they would not have survived and held their place as conventional accomplishments of the leisure class.
Thorstein Veblen, The Theory of the Leisure Class. An Economic Study in the Evolution of Institutions (1899)