As many readers know, PPE (philosophy, politics, and economics) is an increasingly popular academic program in universities and colleges across the country. These are typically degree programs for undergraduates, where students can major and/or minor in PPE. (I direct such a program at BGSU). But there is also a field of study we might call PPE research, and while we are doing more of it than ever before, especially at the PPE Society meeting, and PPE Society panels at the meetings of the APA and APSA, it is hard to characterize precisely what PPE research is.
Here I want to take a stab at that problem by trying to describe what I take to be core PPE research. In doing so, I’ll invariably exclude some topics that people think of as PPE research, since self-conscious research in the area is fairly new and practitioners don’t quite agree about the core topics.
In my view, PPE research uses multiple disciplinary methods to study human cooperation and conflict, understood maximally broadly. More briefly, PPE research is the comprehensive study of social order and disorder.
I. Core PPE Research Topics
Core PPE research includes research in formal reasoning, such as utility theory, the theory of exchange, game theory, social choice theory, and public choice theory, all of which are concerned with individual rational choice, or rational choice between persons. The theory of exchange covers positive-sum games, game theory covers strategic interaction and conflict, and social choice theory covers collective choice. All these fields provide us with models for understanding social interaction. PPE research also includes the study of norms and conventions, both of which are patterns of behavior central to social order.
I count some branches of moral psychology as PPE research, such as the study of sympathy, guilt, shame, blame, and punishment, and trust, all attitudes instrumental in forming social order, as well as cognitive science, in order to understand how humans actually make decisions.
PPE research includes the study of the history of institutions, with an eye to how different groups have maintained or failed to maintain social cooperation, as well as the evolution of cooperation, morality, and large-scale cooperation and conflict.
PPE research involves philosophical analysis in order to resolve certain difficulties that arise in formal reasoning, the theory of human behavior, to delineate the boundaries of certain concepts, and to formulate methodological principles for how to understand human cooperation, its causes and consequences. Moral philosophy also helps with the study of social morality, that is, the study of moral orders that invoke moral concepts, rules, and attitudes.
On top of this, we can include philosophical topics in social philosophy, such as the study of race and gender, and other features of personal identity and psychology and moral concern that figure into understanding social orders, such as how to understand patterns of oppression.
One could also add the study of the law, in particular how legal systems evolve and develop, and how they are reformed.
II. How PPE Research Interacts with Normative Theorizing
In my view, PPE research is not centrally about identifying true moral principles or principles of justice. That’s political philosophy, which is continuous with PPE, but distinct from it. Some modes of theorizing about justice will seem central to PPE, but that’s because some theories of justice understand justice as derived from our ability to solve coordination problems, like contractarianism. Contractarian theories of justice, for that reason, seem closer to PPE research than, say, perfectionist theories of justice. Normative ethics is not PPE research either. The contest between virtue ethics, deontology, and consequentialism isn’t core PPE research.
Accordingly, I don’t see theories of distributive justice as core PPE research. Rawls-Nozick, again, is political philosophy.
That said, I do think PPE research includes how to apply theories of justice and normative ethical theories to reform norms and institutions. PPE research might include, for instance, how to organize an economy to maximize utility, or how to structure a constitution such that it protects certain rights. So PPE research can cover the application or institutionalization of certain moral or political principles.
III. PPE Methods
Finally, a central element of core PPE research is the appeal to multiple methods of problem-solving. In particular, PPE research typically appeals to two fundamental methods of reasoning: philosophical reasoning (rational argument and conceptual analysis) and economic reasoning (choice under scarcity). Not all PPE research appeals to both methods, but core PPE research topics often employ both.
And of course, we can’t leave out the much more eclectic method of political science, which in some ways makes political science closer to PPE by way of method than philosophy or economics by themselves.
I wish I had more insight into the methods of political science other than that they’re diverse. So here’s an attempt to characterize what makes political science unique.
From my vantage point, political scientists are far more comfortable outlining the role ideas play in explaining how institutions function. Philosophers like to think they’re drawing philosophical ideas from conceptual space rather than history and institutional practice, and economists don’t like to explain events in terms of ideas at all. For example, philosophers and economists only periodically talk about ideology as an explanatory category, but political scientists are much more inclined to do so.
Political scientists also have more to say about how institutions shape ideas, such as how historical conditions give rise to ideology.
So perhaps political science has its particular pulse on the idea-institution explanatory nexus.
In conclusion, I grant that one can imagine lots of stuff that counts as PPE that doesn’t fit my description, but I think this stuff is closer to the periphery. The heart of PPE research is the study of social order and disorder.
Eric Schliesser has offered a related but importantly distinct account of PPE research.