Facts are facts, whether they are stated or not. Different and even incommensurable languages may be needed to describe the facts. For Searle, long before there were humans, there were brute physical facts. Eventually, as consciousness appeared, there came to be brute mental facts. However, as humans developed, there has come into existence a new kind of fact, social fact,generated by human practices and human attitudes.
Social facts come into existence through human construction.
Much of the book consists of working out some of the details of how social reality is constructed. For Searle, these social constructions are realities consisting of objective facts. But the social realities and the physical realities are not separate and independent. The brute physical facts could exist without there being a U. S., but there could not be a U. S. without the brute physical facts. The overlay exists by virtue of the common intentions, functions, and rules adopted by humans.