I'm sure everyone has thought at some time, is this real? But the important question is what makes something real? Most of the time the things we experience in this world are just constructs. We have opinions about everything, and we experience the world through that lens. Social constructionism is a theory that knowledge and many aspects of the world around us are not real in and of themselves. They only exist because we give them reality through social agreement. Things like nations, books, even money don't exist in the absence of human society. Nations are groups of people who happen to share a language or history. Books are paper with scribbles. And money is just pieces of paper and metal that have no value other than what we have assigned them. The concept of the self can be considered a social construct, too. Our identity is created by interactions with other people and our reactions to the expectations of society. There are two threads of social constructionism, the weak and the strong. Weak social constructionism proposes that social constructs are dependent on brute facts, which are the most basic and fundamental and don't rely on any other facts. Brute facts are kind of difficult to understand because it is so strange to think about something that can't be explained by something else. So for example, take the computer screen you're looking at. Your screen works because of changing voltages and bits of metal, which can be explained by movements of subatomic particles, which are made from quarks, so on and so forth. None of those are brute facts. The brute fact is what explains quarks or what explains the explanation of quarks. Those brute facts are separate from institutional facts which are created by social conventions and do rely on other facts. So for example, money depends on the paper that we have given value. Strong social constructionism, on the other hand, states that the whole of reality is dependent on language and social habits, that all knowledge is a social construct, and that there are no brute facts. So it would say that we created the idea of quarks and everything we use to explain it. There are no facts that just exist. The main criticism to social constructionism is that it doesn't consider the effect of natural phenomenon on society. And, at least for strong social constructionism, it even has difficulty explaining those phenomena because they don't depend on human speed or action. Strong social constructionism only explains reality through the thoughts of humans, not by using fundamental brute facts.