Neurofunctional Prudence and Morality

A Philosophical Theory 

(forthcoming February 2020, Routledge)


Philosophers across many traditions have long theorized about the relationship between prudence and morality. Few clear answers have emerged, however, in large part because of the inherently speculative nature of traditional philosophical methods. This book aims to forge a bold new path forward, outlining a theory of prudence and morality that unifies a wide variety of findings in neuroscience with philosophically sophisticated normative theorizing.


Chapter 1 - Outline of the Behavioral Neuroscience of Prudence and Morality: This chapter outlines the emerging behavioral neuroscience of prudence and morality, along with how the findings raise normative and descriptive explanatory questions. The chapter begins by outlining how prudential and moral cognition involve mental time-travel (the capacity to imaginatively simulate different possible pasts and futures), other-perspective-taking (the capacity to imaginatively simulate other people’s perspectives), and risk-aversion. The chapter then outlines seventeen distinct regions of the human brain’s Default Mode Network (DMN)—a region involved in daydreaming, mind-wandering, thinking about oneself and others, remembering the past, and imagining the future—that have been implicated in moral judgment and sensitivity across a wide variety of tasks. In the process, the chapter outlines how stimulation and inhibition of particular DMN regions and capacities, including the temporoparietal junction (TPJ), have been found to have bidirectional effects on prudential and moral cognition. Finally, the chapter suggests the findings outlined raise normative questions about why particular brain regions and capacities should be involved in prudential and moral cognition, descriptive questions about how they are involved in both forms of cognition, and appear to cohere poorly with some dominant views in moral philosophy.

Chapter 2 - Outline of a Theory of Prudence: This chapter outlines a new normative theory of prudence and descriptive psychological theory of prudential cognition. The chapter begins from the common premise in the literature that prudence is normatively a matter of acting in ways that have the greatest-expected aggregate lifetime utility. The chapter then suggests that because life as a whole is profoundly uncertain, prudence requires acting on principles that are rational from a standpoint of radical diachronic uncertainty—from what Donald Bruckner calls a ‘Prudential Original Position’, a model similar to John Rawls’ famous original position, but where an individual agent is situated behind a veil of ignorance applied to their own life. Following Bruckner, I assume that minimax regret—the principle of acting in ways that minimize the maximum amount of regret an action might result in—is the most rational principle in the Prudential Original Position, and that this principle converges with maximizing expected aggregate lifetime utility the more an agent cares about the past and future. The chapter then constructs a detailed theory of how Bruckner’s account coheres with and appears supported by a specific form of ‘moral risk-aversion’ that prudent people typically engage in and progressively internalize across childhood, adolescence, and adulthood. 

Chapter 3 -  Derivation of Morality from Prudence: This chapter derives and refines a novel normative moral theory and descriptive theory of moral psychology—Rightness as Fairness—from the theory of prudence defended in Chapter 2. The chapter briefly summarizes Chapter 2’s finding that prudent agents typically internalize ‘moral risk-aversion’. The chapter then outlines how this prudential psychology leads prudent agents to want to know how to act in ways they will not regret in morally salient cases, as well as to regard moral actions as the only types of actions that satisfy this prudential interest. The chapter then uses these findings to defend a new derivation of Marcus Arvan’s theory of morality, Rightness as Fairness, showing how the derivation successfully defends Rightness as Fairness against a variety of objections. Additionally, the chapter outlines how Arvan’s theory of prudence can help substantiates the claim that Rightness as Fairness unifies a variety of competing moral frameworks: deontology, consequentialism, contractualism, and virtue ethics. Finally, the chapter shows how Chapter 2’s theory of prudence entails some revisions to Rightness as Fairness, including the adoption of a series of Rawlsian original positions to settle prudential, moral, and social-political issues under ideal and nonideal circumstances.

Chapter 4 - A Unified Neurofunctional Theory of Prudence and Morality: This chapter utilizes seven principles of theory-selection to compare the theory of prudence and morality to alternatives. The chapter first argues that there are two possible ways that a theory of prudence and morality may explain relevant target phenomena: (1) as a normative teleofunctional explanation of why particular phenomena findings in behavioral neuroscience should be the case, and (2) as a descriptive functional explanation of how prudential and moral psychology actually function. The chapter then argues that in order to evaluate how successful a theory is in both respects, theories of prudence and morality should be judged according to seven principles of theory-selection adapted from the sciences, including principles of internal and external coherence, explanatory power, unity, parsimony, fruitfulness, and ‘firm observational foundations.’ Finally, the chapter outlines how Arvan’s unified theory of prudence and morality—Prudence and Morality as Fairness to Oneself and Others—appears to satisfy all seven principles of theory-selection more successfully than other existing normative moral theories and descriptive theories of moral psychology.

Chapter 5 - Replies to Potential Concerns, and Avenues for Future Research: This chapter responds to potential concerns to the theory of prudence and morality defended. The chapter first addresses the concern that the theory is overly speculative, arguing that the theory is normatively and descriptively promising and thus worthy of further philosophical and empirical examination. The chapter then addresses the concern that the theory commits the naturalistic fallacy and violates the ‘is-ought gap’, arguing that the theory commits neither error. Third, the chapter addresses the concern that there may be counterexamples to Arvan’s theory of prudence: individuals who appear to live in prudentially successful ways while not appearing to have internalized the form of ‘moral-risk aversion’ that Chapters 2 and 3 of Neurofunctional Prudence and Morality argued serve as the foundation for normative moral philosophy and descriptive moral psychology. The chapter argues that it is an empirical question whether such counterexamples are genuine and, by extension, whether there really are individuals to whom morality does not normatively apply—an implication the chapter argues for taking seriously. Finally, the chapter addresses the concern that Arvan’s theory is at most a theory of how morality is prudent, not a theory of morality per se.