Any normative political theory presumes an understanding of the positive processes of its proposed institutional arrangements. As such, I believe that formal theory (viz. game theory or social choice theory), by offering a better understanding of the positive processes of different kinds of political institutions, can greatly help the normative theorizing of political theorists by showing what can and what cannot be realistically achieved from the practical implementation of their proposed political theory. Formal theory can also help us clarify the precise logical relationships between fundamental normative concepts and, thereby, allow us to understand which set of normative concepts can be coherently endorsed without committing any logical inconsistencies.
You may find my "Research Statement" here.
Welfarism and Continuity in Ethical Theory: A Formal Comparison of Prospect Utilitarianism vs. Sufficientarianism (Appendix) (with Susumu Cato)
(Conditionally Accepted on 15-Jun-2025 for Economics & Philosophy)
This paper offers a formal analysis of continuity, welfarism, value satiability, and lifeboat cases to critically assess recent defenses of sufficientarianism by Ben Davies and Lasse Nielsen in response to Hun Chung’s Prospect Utilitarianism (PU). It demonstrates how precise formal definitions help resolve conceptual ambiguities and sharpen philosophical argumentation in distributive ethics. Without such precision, one risks misidentifying or mischaracterizing important normative concepts and theories, leading to confusion or strawman critiques. By highlighting these risks, the paper underscores the methodological importance of precise definitions and formal analysis in ensuring clarity, consistency, and rigor in ethical theorizing.
How Nozick's Rectification Principle Redefines the Minimal State (with Jacob Watkins-Strand)
(Published Online in Erkenntnis)
Robert Nozick recognized that calls for distributive justice represented the most salient justification for extending the state beyond his preferred minimal form. He therefore made it his project to demonstrate that distributive justice could be achieved under the minimal state. Achieving distributive justice, however, requires the effective functioning of the rectification principle: rectification represents the only mechanism that can correct distributions resulting from past injustices that deviate from repeated historical applications of the principles of justice in acquisition and transfer. This makes Nozick’s principle of rectification the linchpin of the minimal state: the success of the minimal state entirely depends on whether it can successfully implement the rectification principle without expanding its state apparatus. In this paper, we demonstrate that under traditional understandings of the minimal state, the rectification principle fails to correct historical injustices even in maximally simplified and charitable scenarios. We propose, and model, a solution – the state as a fractional-reserve lender – that would render the rectification principle many-fold times more effective and robust. This is, however, a consequential modification: while this improved operation of the rectification principle does defend against wholesale extensions of the minimal state, it requires a reconceptualization of the minimal state as consisting of a central bank in addition to its police, courts, and army.
Formal Models in Normative Political Theory (with Brian Kogelmann )
(Published in the Journal of Theoretical Politics 36 (3): 256-274)
In this paper, we argue that formal models can serve as a very useful methodological tool in doing normative political theory by: (a) serving as more precise and rigorous versions of the political theorist’s thought experiments; (b) allowing us the rigorously examine the coherence and logical consistencies in our core normative commitments; and (c) informing real-world institutional and policy design.
(The Impossibility of) Deliberation-Consistent Social Choice (with Tsuyoshi Adachi and Takashi Kurihara )
(Published Online in the American Journal of Political Science 68(3), 1075-1088)
(Link to the Waseda University Press Release for the general public)
There is now a growing consensus among democratic theorists that we should incorporate both ‘democratic deliberation’ and ‘aggregative voting’ into our democratic processes, where democratic deliberation precedes aggregating people’s votes. But how should the two democratic mechanisms of deliberation and voting interact? The question we wish to ask in this paper is which social choice rules are consistent with successful deliberation once it has occurred. For this purpose, we introduce a new axiom, which we call “Non-Negative Response toward Democratic Deliberation (NNRD).” The basic idea is that if some individuals change their preferences toward other individuals’ preferences through successful deliberation, then the social choice rule should not make everybody who has successfully persuaded others through reasoned deliberation worse-off than what they would have achieved without deliberation. We prove an impossibilty theorem that shows that there exists no aggregation rule that can simultaneously satisfy (NNRD) along with other mild axioms that reflect deliberative democracy’s core committment to unanimous consensus and political equality. We offer potential escape routes: however, it is shown that each escape route can succeed only by compromising some core value of deliberative democracy.
STABLE DYSTOPIA: A Critique of the Circular Definition of Stability in Nozick’s Model of Utopia (with Susumu Cato)
(Published Online in Analysis)
In Part III of Anarchy, State, and Utopia, Robert Nozick presents what he calls “the model of possible worlds” to examine the formal properties of utopia, defined as “the best of all possible worlds.” (Nozick 1974: 298). The basic idea is that each person is given the power to create any possible world and its inhabitants by imagining them. Two definitions of stability have been proposed: (a) the non-circular definition according to which a world is stable if and only if nobody can imagine a better world; and (b) the circular definition according to which a world is stable if and only if nobody can imagine a better world that is also stable. In this paper, we prove four theorems (viz., the indeterminacy theorem, the stable dystopia theorem, the nobody’s utopia theorem, and the redundancy theorem) that demonstrate that the circular definition of stability is fundamentally flawed.
When Utilitarianism Dominates Justice as Fairness: An Economic Defense of Utilitarianism from the Original Position (Published Online in Economics and Philosophy 39(2): 308-333)
Link to Presentation Video: https://youtu.be/doXPpK2Xxc8
The original position together with the veil of ignorance have served as one of the main methodological devices to justify principles of distributive justice. Most approaches to this topic have primarily focused on the single person decision-theoretic aspect of the original position. This paper, in contrast, will directly model the basic structure and the economic agents therein to project the economic consequences and social outcomes generated either by utilitarianism or Rawls’s two principles of justice. It will be shown that when the differences in people’s productive abilities are sufficiently great, utilitarianism dominates Rawls’s two principles of justice by providing a higher level of overall wellbeing to every member of society. Whenever this is the case, the parties can rely on the Principle of Dominance (which is a direct implication of instrumental rationality) to choose utilitarianism over Rawls’s two principles of justice. Furthermore, when this is so, utilitarianism is free from one of its most fundamental criticisms that it “does not take seriously the distinction between persons.” (Rawls 1971/1999: 24)
Chain-Connection, Close-knitness, and the Difference Principle (Published Online in the Journal of Politics 84(4): 2305-2311)
JOP Blog Entry: "Would Helping the Poor Benefit Everybody?"
When distributing the benefits produced by social cooperation, Rawls’s difference principle targets a specific group, i.e. the least advantaged group, and requires its expectations to be maximized. One natural worry is whether the practical application of the difference principle comes with a significant cost to other groups in society. Rawls was quite aware of this potential worry and gave his earnest efforts to respond to it. His solution comes from his notions of chain connection and close-knitness. (Rawls 1971/1999: 69-72) Rawls’s claim was that whenever society satisfies both chain connection and close-knitness, the practical implementation of the difference principle will (a) always lead to strict Pareto improvements, and, as a result, (b) the final state will be Pareto optimal. In this paper, it will be shown that under close scrutiny neither of these claims holds even when society is both chain-connected and close-knit.
Prospect Utilitarianism and the Original Position (Published Online in Journal of American Philosophical Association 9(4): 670-704)
Suppose we assume that the parties in the original position took Kahneman and Tversky’s prospect theory as constituting their general knowledge of human psychology that survives through the veil of ignorance. How would this change the choice situation of the original position? In this paper, I present what I call “prospect utilitarianism.” Prospect utilitarianism combines the utilitarian social welfare function with individual utility functions characterized by Kahneman and Tversky’s prospect theory. I will argue that, once prospect utilitarianism is on the table, Rawls’s original arguments in support of justice as fairness as well as his arguments against utilitarianism are, at best, inconclusive. This shows that how implausible a choice for utilitarianism in the original position is heavily depends on what one assumes to be general knowledge of human psychology that the original contracting parties know.
Locke's State of Nature and Its Epistemic Deficit: A Game-Theoretic Analysis (Published Online in Synthese)
Locke rejected anarchism. Locke defended the universal necessity of political governments on the grounds that the state of nature will occasionally generate the inconveniences of war. The standard interpretation of Locke identifies three main causes of war in the state of nature: the lack of a common judge, moral disagreement over the law of nature, and self-love. In this paper, I argue that the combination of these three factors does not guarantee that war will occur in every plausible scenarios of Locke’s state of nature. Instead, in order for war to occur at least sometimes in every plausible scenario of Locke’s state of nature, there has to be some sort of epistemic deficit. In this paper, I show via the tools of modern game theory, how Locke’s state of nature may occasionally generate war by two kinds of epistemic problems implied by Locke’s own epistemology: (a) disagreements in subjective probabilities, and (b) uncertainty in other people’s moral motivation to use force to enforce the law of nature. The fact the war occurs primarily because of such epistemic problems suggests a role for a very limited form of government; namely, the ultra-ultra-minimal state, whose role is confined to solving such epistemic problems.
On Choosing the Difference Principle behind the Veil of Ignorance: A Reply to Gustafsson (The Journal of Philosophy 118 (8): 450-462)
In a recently published paper (“The Difference Principle Would Not Be Chosen behind the Veil of Ignorance”. The Journal of Philosophy 115 (11): 588-604), Johan E. Gustafsson argues that “the parties [in Rawls’s original position] would not choose the Difference Principle.” (589) Gustafsson’s main strategy was to show that Rawls’s difference principle in both of its ex post and ex ante versions imply counterintuitive distributional prescriptions in a few contrived examples. The purpose of this paper is to precisely demonstrate exactly how Gustafsson’s arguments have failed to show that the difference principle would not be chosen behind the veil of ignorance.
A Formal Theory of Democratic Deliberation (with John Duggan) (American Political Science Review 114 (1): 14-35, Open Access)
Link to Presentation Video: https://youtu.be/2IrwpHxJUGk
Inspired by impossibility theorems of social choice theory, many democratic theorists have argued that aggregative forms of democracy cannot lend full democratic justification for the collective decisions reached. Hence, democratic theorists have turned their attention to deliberative democracy, according to which “outcomes are democratically legitimate if and only if they could be the object of a free and reasoned agreement among equals.” (Cohen 1997a: 73) However, relatively little work has been done to offer a formal theory of democratic deliberation. This paper helps fill that gap by offering a formal theory of three different modes of democratic deliberation: myopic discussion, constructive discussion, and debate. In either form of discussion, positions are considered according to an exogenous protocol and arguments applied to them, whereas in a debate, two participants who have diametrically opposed preferences take turns and propose positions with supporting reasons/arguments. We show that myopic discussion suffers from indeterminacy of long run outcomes, while constructive discussion and debate are conclusive, i.e., both forms of deliberation converge to a position that is maximally justified according to at least one reason/argument. Finally, unlike the other two modes of deliberation, debate is path independent and converges to a unique compromise position, irrespective of the initial status quo.
The Well-Ordered Society Under Crisis: A Formal Analysis of Public Reason vs. Convergence Discourse (American Journal of Political Science 64 (1):82-101, Open Access)
A well-ordered society faces a crisis whenever a sufficient number of non-compliers intrude society. This has a potential to destabilize political order. This paper provides a formal analysis of two competing solutions to the problem of political stability offered in the public reason liberalism literature – namely, using public reason or using convergence discourse to restore political stability in the well-ordered society. The formal analyses offered in this paper show that using public reason fails completely, while using convergent discourse, although doing better, has its own critical limitations that have not been previously recognized properly.
Rawls's Self-Defeat: A Formal Analysis (Published Online in Erkenntnis, Open Access)
One of John Rawls’s major aims, when he wrote A Theory of Justice, was to present a superior alternative to utilitarianism. Rawls’s worry was that utilitarianism may fail to protect the fundamental rights and liberties of persons in its attempt to maximize total social welfare. Rawls’s main argument against utilitarianism was that, for such reasons, the representative parties in the original position will not choose utilitarianism, but will rather choose his justice as fairness, which he believed would securely protect the worth of everybody’s basic rights and liberties. In this paper, I will argue that, under close formal examination, Rawls’s argument against utilitarianism is self-defeating. That is, I will argue that Rawls’s own reasons, assumptions, and the many theoretical devices he employs demonstrably imply that the representative parties in the original position will choose utilitarianism instead of justice as fairness. I will show this through a formal model.
Directional Equilibria (with John Duggan) (Journal of Theoretical Politics 30 (30): 272-305)
We propose the solution concept of directional equilibrium for the multi-dimensional model of voting with general spatial preferences. This concept isolates alternatives that are stable with respect to forces applied by all voters in the directions of their gradients, and it extends a widely (but not well-) known concept from statistics for Euclidean preferences. We establish connections to the majority core, Pareto optimality, existence and closed graph, and generic local uniqueness and stability of the solution, and we provide non-cooperative foundations in terms of a local contest game played by voters.
The Impossibility of Liberal Rights in a Diverse World (Published Online in Economics and Philosophy 35(1): 1-27)
A defining characteristic of a liberal democratic society is the assignment of basic rights and liberties that protect each person’s private sphere. Hence, social choice made in a liberal democratic society must at the very least be consistent with the exercise of each person’s basic rights. However, even when everybody agrees to this basic principle, there could still remain irreconcilable social conflict and disagreement when it comes to the specific assignment of basic rights. This is especially so in a pluralistic society where there is a clash among radically different and incompatible world views. Philosophers have now started to focus on this issue, which now goes by the name “perspectival diversity.” This paper extends the basic social choice theoretic framework of liberal rights by extending the domain to include individual perspectives alongside individual preferences. In this new framework, different individuals are able to see or perceive the same social alternative differently based on their own unique perspectives. The formal results of the paper imply that generating a viable social choice that is consistent with the assignment of basic rights can quickly break down once we start to increase the level of perspectival diversity in society.
Diversity and Rights: a Social Choice Theoretic Analysis of the Possibility of Public Reason (with Brian Kogelmann) (Published Online in Synthese)
Public reason liberalism takes as its starting point the deep and irreconcilable diversity we find characterizing liberal societies. This deep and irreconcilable diversity creates problems for social order. One method for adjudicating these conflicts is through the use of rights. This paper is about the ability of such rights to adjudicate disputes when perspectival disagreements – or disagreements over how to categorize objects in the world – obtain. We present both formal possibility and impossibility results for rights structures under varying degrees of perspectival diversity. We show that though perspectival diversity appears to be a troubling problem for the prospect of stable social order, if rights are defined properly then disagreements can likely be resolved in a consistent manner, achieving social cooperation rather than conflict.
John Rawls’s most mature notion of political order is “stability for the right reasons.” Stability for the right reasons is the kind of political order that Rawls hoped a well-ordered society could ideally achieve. In this paper, I demonstrate through the tools of modern game theory, the instability of “stability for the right reasons.” Specifically, I will show that a well-ordered society can completely destabilize by the introduction of an arbitrarily small number of non- compliers whenever individuals fail to achieve full common knowledge ever so slightly.
Prospect Utilitarianism: A Better Alternative to Sufficientarianism (Published Online in Philosophical Studies)
Ever since the publication of Harry Frankfurt’s “Equality as a Moral Ideal” (1987), the doctrine of sufficiency has attracted great attention among both ethical theorists and political philosophers. The doctrine of sufficiency (or sufficientarianism) consists of two main theses: the positive thesis states that it is morally important for people to have enough; and the negative thesis states that once everybody has enough relative inequality has absolutely no moral importance. Many political philosophers have presented different versions of sufficientarianism that retain the general spirit of what Frankfurt had proposed in his seminal work. However, all of these different versions of sufficientarianism suffer from two critical problems: (a) they fail to give right answers to lifeboat situations, and (b) they fail to provide continuous ethical judgments. In this paper, I show a version of utilitarianism that solves these problems while retaining the major attractions of sufficientarianism. I call it “prospect utilitarianism.” In addition, I show that prospect utilitarianism can avoid standard objections to utilitarianism and has aspects that can appeal to both prioritarians and egalitarians as well.
A Game-Theoretic Solution to the Inconsistency between Thrasymachus and Glaucon in Plato's Republic (Ethical Perspectives 23(3): 383- 410)
In Book 1 of Plato’s Republic, Thrasymachus contends two major claims: (1) justice is the advantage of the stronger, and (2) justice is the good of the other, while injustice is to one’s own profit and advantage. In the beginning of Book II, Glaucon self-proclaims that he will be representing Thrasymachus’ claims in a better way, and provides a story of how justice has originated from a state of nature situation. However, Glaucon’s story of the origin of justice has an implication that justice is the advantage of the weak rather than the stronger. This is inconsistent with Thrasymachus’ first claim which states that justice is the advantage of the stronger. This is a problem for Glaucon since Glaucon is supposed to be representing Thrasymachus’ original claims in a better way. In this paper, I provide two solutions to this puzzle with the help of elementary game theory.
Hobbes's State of Nature: A Modern Bayesian Game-Theoretic Analysis (Journal of the American Philosophical Association 1(3): 485-508)
Hobbes’s own justification for the existence of governments relies on the assumption that, without a government, our lives in the state of nature would result in a state of war of every man against every man. Many contemporary scholars have tried to explain why universal war is unavoidable in Hobbes’s state of nature by utilizing modern game theory. However, most game-theoretic models that have been presented so far do not accurately capture what Hobbes deems to be the primary cause of conflict in the state of nature – which is uncertainty, rather than people’s egoistic psychology. Any game- theoretic model that does not incorporate uncertainty into the picture is, therefore, I claim, the wrong model. In this paper, I use Bayesian game-theory to show how universal conflict can break-out in the state of nature - even when the majority of the population would strictly prefer to cooperate and seek peace with other people - due to uncertainty about the other person’s type. Along the way, I show that the valuation of one’s own life is one of the central mechanisms that drives Hobbes’s pessimistic conclusion.
Is Harry Frankfurt's "Doctrine of Sufficiency" Sufficient? (Organon F 23 (1): 50-71)
In his article, “Equality as a Moral Ideal”, Harry Frankfurt argues against economic egalitarianism and presents what he calls the “doctrine of sufficiency.” According to the doctrine of sufficiency, what is morally important is not relative economic equality, but rather, whether somebody has enough, where “having enough” is a non-comparative standard of reasonable contentment that may differ from person to person given his/her aims and circumstances. The purpose of this paper is to show that Frankfurt’s original arguments in support for his doctrine of sufficiency have critical problems that Frankfurt himself does not properly recognize. In the end, I will argue that in order to solve these problems the doctrine of sufficiency cannot help but to incorporate certain prioritarian commitments – commitments which many would view as implying economic egalitarianism. This is embarrassing for a doctrine whose raison d’être was mainly to defeat economic egalitarianism.
Psychological Egoism and Hobbes (Filozofia 71 (3): 197-208)
Many commentators think that Hobbes was committed to psychological egoism. Psychological egoism is a theory of human psychology that claims that all human actions are ultimately motivated solely by one’s own self-interest. In this paper, I argue that there are reasons to think that Hobbes was not committed to psychological egoism in any of its plausible formulations.
Understanding Rationality in Hobbes and Hume (Filozofia 69 (8): 687-696)
Many commentators think that Hobbes was committed to an instrumental view of rationality which foreshadows that of David Hume. The Humean conception of instrumental rationality is a conjunction of the following two claims: (a) no preferences or desires can properly be said to be irrational in themselves, and (b) the role of reason or rationality can only be confined to informing the agent with true beliefs about the world, and revealing the most effective means that could satisfy the agent’s current ends whatever they happen to be. In this paper, I argue that, unlike what many people think, a careful reading of Hobbes shows that he was committed to neither of these claims.
Game Theory, Rational Choice Theory, and the Prisoner's Dilemma: Some Clarifications (The Korean Journal of Philosophy of Science 17 (3): 23-51)
There seems to be critics who think that game theory can provide very little insights in doing empirical social scientific research or normative political theory/political philosophy. This is because these people tend to think that game theory is committed to some highly contestable theory of human psychology; namely, that human beings either are or should be primarily motivated by their own exclusive self-interest. From this, critics tend to think that game theory is defective both as a normative theory of action as well as a descriptive theory of action. After explaining the basics of game theory, I will try to show that such criticisms are mostly based on a general misunderstanding of game theory. In the end, I will argue that game theory is simply a mathematical tool that could be used to model any strategic interaction for many different purposes, and is not committed to any substantial theories of human nature.
경제학적 도구들과 사고방식은 윤리학에 어떤 도움을 주는가? (단행본: <처음 읽는 윤리학> (동녘)에 수록된 논문)