Functionalism is a theory based on the idea that everything in society has a function and is necessary. The society won't survive without every aspect of it, so nothing is obsolete or unnecessary. The needs of society and the individuals within that society are very similar, so it is not necessary to rebel against the way society is or the way a particular individual may be conducting himself or herself. All of what is seen in society is needed in some way for functionality, even if not every person in that society understands why a particular thing is necessary for the survival of that society and/or one or more of the individuals within it.