I believe we are born in human form to grow and learn. As we learn we grow and evolve. If we fail the lesson we are recycled and have to be reborn to try and learn it over and over until we get it.
Imagine you are in a totally dark room with not a speck of light and you take a pin and poke through the wall, now there is just a tiny pin hole of light that comes in, well guess what? You are no longer in the dark, light is coming in.