This thesis explores the relationship between rationality and morality. I ask questions about the prudential rewards of being moral, the evolutionary origins of our moral norms and implications for morality if we accept a more robust theory of rationality. To investigate one's prudential reasons to be moral, I use game theory. Specifically focusing on the Prisoner's Dilemma, I mathematically demonstrate its seemingly surprising conclusion. Philosophers like David Gauthier are troubled by the outcome of the Prisoner's Dilemma and its potential implications for morality, so I examine his response. I also use game theory to think about the evolution of norms over time. Using the work of Cristina Bicchieri, I question the assumptions on which traditional game theory is based and explore a new approach. Lastly, I deviate from the mathematical philosophy and explore the work of Donald Davidson. I give an account of what it means to be moral, if we accept his theory of rationality. Each author comes to the table asking different questions and making different assumptions. This variety is an asset. Rather than revealing some deep truth about the relationship between rationality and morality, I conclude with the importance of examining the relationship from all angles, through asking different questions and taking different approaches.


Riley, Evan

Second Advisor

Pierce, Pam


Mathematics; Philosophy


Ethics and Political Philosophy | Mathematics

Publication Date


Degree Granted

Bachelor of Arts

Document Type

Senior Independent Study Thesis



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