in this life all of as are sleeping scientist. we never know what type of creation we made before. sometimes during sleep we don't recognize the things that our body do. there are times we create dreams because of to much thinking on the things we wanted to happen. sometimes we dreams because our spirit communicate to our physical body.  there are many instances upon sleeping that temporal mind can't explain only our spiritual mind do. how it does happen, it happen when we are too stress or so tired because of our job. we heard our spirit speaking to us that we are tired and we need rest so that our cells and nerves we work own us to refresh those energy we lost because of to much work. we  need rest because our mind and body will stop releasing the energy that is need inside our human body to continue active. this is called body enrgyzation