Literature is one of how ideals that are spread. It’s particularly effective in that most novels are lengthy enough so that ideas can be examined in depth, and presented from different perspectives. The author has something that he or she wants to relate to and has the perfect vehicle for it within a story. It works so well, that oftentimes times the themes are implanted without your realization!

Literature influences society in at least three vital ways-

1. Literature helps to resolve societal conflicts. It gives us a platform to vent out our negative emotions and better understand the perspective of others. This allows the social machine to function smoothly avoiding a disastrous engine failure. What might’ve led to a full-blown warfare between nations gets fought out in a series of mock combats between pens and papers. Our primal instincts of violence and aggression are thereby channeled into something constructive.
2. Literature has healing properties and acts as a form of art therapy. Art making, which includes writing stories and poems, acts as a coping mechanism to deal with a diverse range of psychological problems, fosters a sense of positive identity and allows people to focus on positive life experiences relieving the underlying physical and/or mental pain and suffering they’re going through. Professional art therapists deal with a broad range of clients all the way from patients suffering from mental disorders like dementia, schizophrenia, autism etc. to cancer patients, the elderly, the ill, veterans, trauma survivors, eating disorder patients or even average people to help them resolve family and personal issues, work-related stress and burnout issues etc. Art therapy is also used in disaster relief and crisis intervention to alleviate suffering and allow the victims of natural or manmade disasters to cope with their traumatic experiences.
3. Myth-making and meaning-making are what we do as human beings in order to make sense of the world around us and our place in it as individuals, tribes or members of the same species in general. Schools of philosophy and religions have sprung up all over the world to fulfill this common need. What begins in storytelling ends up in legislation. One cannot imagine Montesquieu and his subsequent impact on constitutions around the globe without the vast body of Christian, Renaissance, Enlightenment and classical liberalism literature that nurtured his fertile mind in the first place. Literature is at the very core of our social evolution as a species and it shapes and revises our norms, values, moral codes, beliefs, symbols, taboos, folk culture etc. in each subsequent generation for better or worse. Hopefully, for the progressively better! Literature is also perhaps the best propaganda tool to promote a particular worldview or ideology. The fact that Christianity is the largest religion on the planet goes hand in hand with the fact that the Bible is the best-selling book of all time as well.

I’m sure there are many other reasons out there as well.