One of the theories brought forward on dreams is that a person experiences dreams as a way to strengthen his semantic memories. The person experiences this during the rapid brain activity stage of sleep where information flow in the brain is greatly reduced. A person then experiences a narrative where distant memories and ideas experienced during the day are either erased or recorded into the long term memory this is what normal people refer to as a dream. Continued research further stated that they can be explained as a clean-up where unnecessary information is removed from a person's mind as they sleep.
The other theory is that they play a huge role in helping a person increase their brain activity when they are awake. When one is awake he takes in a lot of information thus when he goes to sleep all the information has to be accommodated by the brain thus they are converted to a dream theme. This theme then has to undergo a test where the ones that can't be stored are discarded while those that can be stored are loaded into the mind. This process then repeats itself all severally during an ordinary sleep night.
A dream can be simply broken down into a normal way for preparing a person's emotionally to handle problems. There is also the evolution theory on dreams where they have no natural purpose and one can go about their natural day to day activities without necessarily having to remember what they dream about. This can be further explained as where a person experiences a dream when their brain starts to piece together random information found in his mind to form a perfect story. These are some of the major theories that have been put forward by scientists alike worldwide, other theories include their use to help a person prepare themselves from real-life threats, emotional imbalance, and social status. These are some of the most famous theories ever put forward in the world.