In Italy, a judge reduced the sentence of a defendant by 1 year in response to evidence for a genetic predisposition to violence. The best characterized of these genetic differences, those in the monoamine oxidase A (MAOA), were cited as especially relevant. Several months previously in the USA, MAOA data contributed to a jury reducing charges from 1st degree murder (a capital offence) to voluntary manslaughter. Is there a rational basis for this type of use of MAOA evidence in criminal (...) court? This paper will review in context recent work on the MAOA gene–environment interaction in predisposing individuals to violence and address the relevance of such findings to murder trials. Interestingly, the MAOA genetic variants impact future violence and aggression only when combined with the adverse environmental stimuli of childhood maltreatment. Thus nature and nurture interact to determine the individual’s risk. Based on current evidence, I argue there is a weak case for mitigation. But should future experiments confirm the hypothesis that individual differences in impulse control and response to provocation found in MAOA-L men (without abuse) are significantly magnified when combined with childhood maltreatment, the case could turn into a stronger one. (shrink)

This paper is an exploration of the nature of what is perhaps the most widely recognized justification for inflicting harm on human beings: the appeal to defense (self-defense and other-defense). I develop and defend a rights-based account of the appeal to defense that takes into account whether and to what degree both the aggressor and his potential victim are morally responsible for the relevant threat. However, unlike most extant rights-based accounts, mine is not a forfeiture account. That is, I do (...) not attempt to explain the permissibility of defense in terms of the aggressor’s loss of a right not to be harmed. Instead I appeal directly to the fact that defense in the relevant cases prevents the aggressor from infringing upon the rights of his potential victim. Accordingly, I call my account a “prevention account.”. (shrink)

When laws or legal principles mention mental states such as intentions to form a contract, knowledge of risk, or purposely causing a death, what parts of the brain are they speaking about? We argue here that these principles are tacitly directed at our prefrontal executive processes. Our current best theories of consciousness portray it as a workspace in which executive processes operate, but what is important to the law is what is done with the workspace content rather than the content (...) itself. This makes executive processes more important to the law than consciousness, since they are responsible for channeling conscious decision-making into intentions and actions, or inhibiting action.We provide a summary of the current state of our knowledge about executive processes, which consists primarily of information about which portions of the prefrontal lobes perform which executive processes. Then we describe several examples in which legal principles can be understood as tacitly singling out executive processes, including principles regarding defendants’ intentions or plans to commit crimes and their awareness that certain facts are the case(for instance, that a gun is loaded), as well as excusatory principles which result in lesser responsibility for those who are juveniles, mentally ill, sleepwalking, hypnotized, or who suffer from psychopathy. (shrink)

In several papers, I have argued for a theory of distributive justice and considered its implications. This theory includes a principle of responsibility that was endorsed by others within an account of defensive force (self-defense and defense of others). Whitley Kaufman criticizes this account which he refers to as the "distributive justice theory of self-defense" (DJ theory). In this paper, I respond to this criticism. I argue that Kaufman presents the theory inaccurately, that his standard of evaluation of the theory (...) is inadequate and that his claim that the theory should be rejected is unconvincing. (shrink)

According to a famous maxim, ignorance or mistake of law is no excuse. This maxim is supposed to represent both the standard and the proper rule of law. In fact, this maxim should be qualified in both respects: ignorance and mistake of law sometimes are, and (perhaps even more often) should be, excused. But this dual qualification only reinforces the fundamental and ubiquitous assumption which underlies the discussions of the subject, namely, that the only ground of exculpation relevant to ignorance (...) or mistake of law is excuse due to lack of (sufficient) culpability. The paper challenges this consensus. I argue that, according to the best conception of justification, ignorance and mistake, including ignorance and mistake of law, could be justified. Generally, ignorance and mistake are justified when based on a rational analysis of the information the agent has and should have. The conceptual possibility of justified ignorance or mistake is demonstrated mainly with respect to ignorance or mistake of law due to reliance on the guidance of public officials or private lawyers. (shrink)

The criminal law depends upon 'commonsense' or 'folk' psychology, a seemingly innate theory used by all normal human beings as a means to understand and predict other humans' behavior. This paper discusses two major types of arguments that commonsense psychology is not a true theory of human behavior, and thus should be eliminated and replaced. The paper argues that eliminitivist projects fail to provide evidence that commonsense psychology is a false theory, and argues that there is no need to seek (...) a replacement theory of behavior for use in the criminal law. (shrink)

This is a review essay of Gardner, John. 2007, Offences and Defences: Selected Essays in the Philosophy of Criminal Law, Oxford: Oxford University Press, 288 pp.