An old essay by John Updike begins, 'We live in an era of gratuitous inventions and negative improvements.' That language is general and abstract, near the top of the ladder. It provokes our thinking, but what concrete evidence leads Updike to his conclusion ? The answer is in his second sentence : 'Consider the beer can.' To be even more specific, Updike was complaining that the invention of the pop-top ruined the aesthetic experience of drinking beer. 'Pop-top' and 'beer' are at the bottom of the ladder, 'aesthetic experience' at the top.