The majority of citizens in our society would believe theorists such as Freud and Darwin are filled with imagination. Little to their knowledge do they know that theorists are the individuals who set the ideas and answers to our respected stand point of view? The definition of a theory is, a set of statements or principles devised to explain a group of facts or phenomena, especially one that has been repeatedly tested or is widely accepted and can be used to make predictions about natural phenomena. This would mean the importance of theories is to help us accept facts to the unknown. The theory would help the problem be solved.
Theorists such as Freud, Darwin, Erickson, etc., facilitated the explanations of the unidentified. Theories were used to help organize one's opinion. You could say a theory is a similar to a hypothesis. In an essay of some sort the hypothesis is a personal opinion or statement, which you have information backing up your thoughts.
The theory is a state of statements to help explain a group of facts. Without a hypothesis an essay would be incomplete and without a theory questions would never be solved. Theories could help one find the meaning of evolution, to the theory of crime. For instance you would stake out the house on the theory that criminals usually return to the scene of the crime, this would help assist comprehension of some sort.
The first step into the scientific method, which is principles and processes of scientific inquiry, is the concept of getting a theory so the problem will be identified. This is the reason I believe theories are necessary to help systematize data and opinions.