Problem
Social fact is a theory created by sociologist Emile Durkheim to describe how values, culture, and norms control the actions and beliefs of individuals and society as a whole.
For example: Marriage: Social groups tend to have the same ideas towards marriage, such as the appropriate age to get married and what a ceremony should look like. Attitudes that violate those social facts, such as bigamy or polygamy in the Western world, are regarded with disgust.
So, what kind of thing are social facts? Are they mental? Are they physical? Are they generalizations or regularities? Durkheim speaks sometimes of "collective minds." Are social facts and collective minds (or mental states) the same thing?