Unger's social theory is premised on the idea of classical social theory that society is an artifact and can be created and recreated. Whereas previous thinkers such as Hegel or Marx backslid at some point and held onto the notion that there was a necessary institutional or historical social development, Unger, in the words of one critic, seeks to "take the idea to the hilt and produce a theory of emancipation that will escape the limitations of liberal and Marxist theories." That limitation is the search for an ideal structure of society that can be foreseen and centrally planned; whereas the emancipation leads to societies with greater institutional flexibility and variation.