Actually we don't, do we? However they can make the seemingly chaotic happenings of life be more easy to understand. Or -if we dig deeper- things might get even more messy. However anything you read on this page should not be considered and believed as fact, since there might no scientific evidence exist for any of these theories, indeed they can be really useful in practice.
Anyway if you are interested in theories or you have some facts that you needed to explain with a theory, feel free to contact me or comment this post.
