This introduction presents an overview of the key concepts covered in the subsequent chapters of this book. The book provides the using empathy to look at social justice in a Hume 'general' way. In other words, the author think empathy can be a way of detaching ourselves from our subjective beliefs in order to think from a moral viewpoint. The author's theory, whilst greatly inspired by Rawls, is offered as an alternative to Rawlsian justice as fairness. As Rawls found with utilitarianism in his time, Rawls's own theory has become so influential as to become, it is fair to say, the dominant political philosophy of our time. Everyone has an equal vote on the outcome. This is achieved not solely by the participatory democratic structure of City Gamma, but also by the necessity of consensus. For any theory of justice to be accepted in the empathy test, it must achieve the status of unanimity, of absolute and complete consensus.