More than two thousand years ago, the Roman poet Horace claimed that literature is "sweet" and "useful." Since then, literature has been traditionally understood, at least in Western cultures, as having the dual purpose of entertaining and educating its audience. Literary texts are constructed as objects of beauty, sources of pleasure and as conveyors of messages and information. While authors often claim no practical purpose for their works, literature constitutes an attempt at persuasively conveying certain values and ideas. The beauty of literature is therefore a part of its rhetoric, a device intended to strengthen the overall persuasiveness and influence of the work on its audience. While the entertaining aspect of literature may be rather obvious, understanding the ideas or values which a text advances is not always a simple task. Part of the problem is the fact that the ideas of a literary text are almost always presented in indirect or "symbolic" form. The fact that literary texts very much seek to convey a message to their audience does not mean that their authors are always fully aware of or even interested in that function of their work. Some of them in fact are quite hostile toward the interpretation of their works and refuse to have anything to do with it.