A novel can probe particular themes or philosophical questions without containing any overt ethical instructions or suggestions. Historically, literature took on the form of fables or parables, and in later years, Christians used writing and literature as a delivery mechanism for scriptural and religious messages. Today, the purpose of story-telling has evolved and stories no longer bear the responsibility of being our society's primary form of moral guidance, leaving authors free to broach other topics in their novels. Even though many readers might prefer a story with some sort of underlying moral, due to our inherent moral nature, literature is entirely subjective, so there could be just as many readers who would prefer to read a novel that could be viewed as frivilous or superficial, purely for the purposes of entertainment. A writer can craft an amoral character by focusing on particular themes "that offer comments or insights about the human experience. These are not lessons, so much as underlying meanings." A theme is the general, recurring idea or concept that runs throughout a work of literature, while the moral is the lesson that the author hopes readers learn once they finish the novel. Examples of a theme include the concept of death, or rebirth, or love, or friendship, and so on, while examples of morals would be "the grass is always greener on the other side," or "do not cheat," or "be generous." A book can easily go without an underlying moral as long as it probes a specific theme instead.