A legal fiction, for present purposes, is a false assumption a court knowingly relies on. The maxim ‘Everybody knows the law’ is an example of a legal fiction. As a statement of fact, the maxim is evidently false. Not even lawyers or judges know all the law. And yet courts apply it, as if it were true, with the result that ignorance of the law is no defence. We therefore say that the maxim is a legal fiction.