The key to Marcuse's thought is his thesis that effective social criticism depends upon a philosophy of two-dimensionality-that is to say, philosophy conceived primarily as a criticism of what is. Alasdair Maclntyre rightly points out that Marcuse thinks the central concern of philosophy should be "with the structure of what can be thought and therefore confronts actuality with possibility." His is a driving passion to correct. And the basic distinction that runs through all of Marcuses works and defines the dual dimension which generates serious thought is the distinction between things as they are and things as they might be.