theories and can they lay claim to the status of an exact science – for example, are economic predictions as reliable as predictions in the natural sciences, and why or why not? Another way of expressing this issue is to ask whether economic theories can state "laws". Philosophers of science and economists have explored these issues intensively since the work of Alexander Rosenberg and Daniel M. Hausman dating to 3 decades ago. Rational choice, decision theory and game theory Philosophical approaches in decision theory focus on foundational concepts in decision theory – for example, on the natures of choice or preference, rationality, risk and uncertainty, and economic agents. Game theory is shared between a number of disciplines, but especially mathematics, economics and philosophy. Game theory is still extensively discussed within the field of the philosophy of economics. Game theory is closely related to and builds on decision theory and is likewise very strongly interdisciplinary. Ethics and justice The ethics of economic systems deals with the issues such as how it is right (just, fair) to keep or distribute economic goods. Economic systems as a product of collective activity allow examination of their ethical consequences for all of their participants. Ethics and economics relates ethical studies to welfare economics. It has been argued that a closer relation between welfare economics and modern ethical studies may enrich both areas, even including predictive and descriptive economics as to rationality of behavior, given social interdependence. Ethics and justice overlap disciplines in different ways. Approaches are regarded as more philosophical when they study the fundamentals – for example, John Rawls' A Theory of Justice (1971) and Robert Nozick's Anarchy, State and Utopia (1974). 'Justice' in economics is a subcategory of welfare economics with models frequently representing the ethical-social requirements of a given theory. "Practical" matters include such subjects as law and cost–benefit analysis Utilitarianism, one of the ethical methodologies, has its origins inextricably interwoven with the emergence of modern economic thought. Today utilitarianism has spread throughout applied ethics as one of a number of approaches. Non-utilitarian approaches in applied ethics are also now used when questioning the ethics of economic systems – e.g. rights-based (deontological) approaches. Many political ideologies have been an immediate outgrowth of reflection on the ethics of economic systems. Marx, for example, is generally regarded primarily as a philosopher, his most notable work being on the philosophy of economics. However, Marx's economic