There are two main aspects to functionalist views of sociology.
First, these views are positivist. That is, they believe that an investigator can look at society in a purely objective and scientific way. Investigators can, thereby, uncover fundamental and scientifically provable facts about society.
Second, these views hold that all parts of society are important for the functioning of society. They say that all aspects of society are like the organs of a living body. That is, they are all necessary and they all play a part in keeping the organism (or society) living and healthy. Thus, functionalists believe that even such things as crime and deviance are important parts of our society that play a valuable role.