Moral Uncertainty and Criminal Justice

Moral Uncertainty and Criminal Justice

Project Description

“Moral uncertainty" arises when ethical theories conflict and we are uncertain which one(s) should guide our conduct/policies.

This project applies the insights of the moral uncertainty literature to intractable debates between penal theorists. The moral uncertainty approach involves taking a step back from the punishment debate and considering the practical implications of the stalemate itself.

The project will investigate ways of assessing the credibility of competing theories; the extent to which areas of consensus between penal theories exist; and whether criminal justice-policy should be based on consensus between plausible theories, rather than seeking to rely on a single viewpoint that is judged to be the most plausible. The project aims 1) to develop a rational response to moral uncertainty about penal theories which could guide criminal justice policymakers and 2) to make a novel contribution by linking the fields of moral uncertainty and punishment theory.

Policy briefings and reports on how the project is progressing will appear on this webpage. I am grateful to the Royal Society of Edinburgh for funding this project.

Research Update:

Many of the doubts about the soundness of the retributive theory of punishment stem from uncertainty about the conception of free will upon which retributivism depends. I have undertaken a literature review of the main positions in the free will debate. The attached document contains definitions of some key concepts. It briefly describes paradoxes faced by 1) retributivists who believe that free will is compatible with determinism and 2) retributivists who believe that free will is incompatible with determinism.

Free Will and Retribution Summary.

Research Update:  

The issue of moral uncertainty has received most attention in connection with the retributive justification of punishment. This is topic is known as "the epistemic challenge to retributivism". I have completed a literature review on the epistemic challenge to retributivism and have written chapters responding to those who defend retributivism against this challenge, and showing how the epistemic argument also applies to non-punitive theories. I am grateful to colleagues for their feedback on these chapters. The attached document summarises some of key points from the literature and highlights some policy implications.

Moral Uncertainty and Criminal Justice Summary 

Research Update:

During this research project, I developed and defended my own response to the problem of moral uncertainty about criminal justice theories, which I call “the convergence requirement”. The document below provides a summary of my main arguments and conclusions. 

The Convergence Requirement Summary.pdf

Related research

The Justice Without Retribution Network

Research Update 

I have conducted an empirical study on lay people’s attitudes to moral uncertainty. I investigated what approach lay people adopt when they lean toward one particular theory of punishment but are not completely certain that their "favourite theory" is correct. Theorists writing on this topic tend to assume that lay people will just put any doubts aside and recommend basing criminal justice policy on the layperson’s favourite theory. Some academics have criticised this simple approach - known as the "My Favourite Theory" approach (MFT) - and have instead defended more complex approaches such the "Maximising Expected Moral Value” approach (MEMV) (for a related approach see:, or “Erring on the Side of Leniency” (ESL) which proposes that that when a reasonable theory about the purpose of punishment recommends a more lenient sentence than the sentence preferred by competing (reasonable) theories, the sentencing judge should opt for the more lenient sentence (ESL is an implication of my “Convergence Requirement”. See “The Convergence Requirement Summary” above.) My results show that, contrary to the assumption in the literature, most lay people in my study did not prefer MFT. Out of 1019 people who answered this question only 11.5% preferred MFT, 42.1% preferred MEMV and 44.4% preferred ESL. Investigating public attitudes to these approaches to criminal justice policy is important, as implementing policies that lack public support can undermine confidence in the criminal justice system, unless effective public education campaigns can foster more support for such policies. The results of my study suggest that when ESL is clearly explained to lay people, there is some public support for this policy proposal.