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Speaker: Walter Sinnott-Armstrong, Professor of Philosophy and Hardy Professor of Legal Studies, Dartmouth College
In a talk entitled "Neuroscience and Responsibility" Professor Walter Sinnott-Armstrong examined several interconnected questions regarding moral responsibility that arise in the context recent neuroscience. Sinnott-Armstrong argued that while findings in neuroscience do not, and plausibly cannot, undermine moral responsibility in a comprehensive way, some neurosceintific findings should lead us to reevaluate the conditions under which we assign moral responsibility to agents.
The talk began with a short examination of arguments to the effect that our growing knowledge of the brain undermines the notion of freedom of the will. The thrust of such arguments is that fashioning neuroscientific explanations of behavior implies determinism and that this, in turn, implies lack of freedom. Prof Sinnott-Armstrong argued that (a) neuroscientific explanations are typically probabilistic, hence do not imply deterministic causation and (b) even if they did imply determinism, that would be compatible with freedom of action. This is because freedom should be understood not as a positive condition involving a lack of a determining casual connection between the agent and his actions, but rather as a lack of excusing causes (compulsion, coercion, etc.). Lack of excusing causes is compatible with deterministic causation.
The bulk of the talk was devoted to two specific connections between neurological phenomena and responsibility. The first involves the case of a 40-year-old male who, following a brain tumor, began to act in sexually criminal ways. This man had little previous use of pornography and no prior record of sexual deviance. In 2000, he started to use pornography, then child pornography, and eventually molested his step-daughter. He was arrested, convicted, and required to choose between prison and a twelve-step in-patient program for sex offenders. Once in the program he propositioned staff members and was taken back to prison. However, before sentencing, a large tumor was found in his right frontal orbital lobe. The tumor was removed and shortly thereafter all the symptoms, including the deviant sexual behavior, had ceased. Ten months later, however, he started to collect pornography again, and it was discovered that the tumor had grown back. The tumor was again removed, and the sexual behavior consequently subsided. Professor Sinnott-Armstrong claimed that in this striking case most people judge that the individual in question is not to be held responsible. But why? The tight correlation between the appearance of his tumor and the deviant behavior strongly suggests a causal connection, but (as was argued earlier) determining causes are typically compatible with responsibility. There does not seem to be any general principle that explains why the existence of a tumor undermines responsibility in such a case. The suggestion that the existence of a tumor implies lack of control by the subject was considered, but Professor Sinnott-Armstrong argued that lack of control is neither a necessary condition for exemption from responsibility nor a sufficient one. Should we add "tumor-induced content" to our list of excusing conditions? As it stands this suggestion is too crude, but perhaps something along these lines is what is implied by a case such as this.
The next topic considered was the question of the efficacy of the will. Professor Sinnott-Armstrong first argued that conscious willing is required for responsibility - it is a near-universal legal requirement, supported by intuitive cases and by reflection on our judgment of phenomena such as sleepwalking. Two lines of thought purport to show that neuroscience undermines conscious willing. The first states that since neuroscience explains action, and does so mechanistically, it is incompatible with conscious willing. Professor Sinnott-Armstrong rejected this line of reasoning, arguing that a mechanistic causal story can co-exist with a mental one, over determining action. Furthermore, he argued that when we are forced to choose between mental and physic-mechanical, often the mental offers the correct level of explanation, capturing the general patterns necessary for explaining action (the argument for this claim has in part to do with multiple reliability).
The second line of argument for the idea that neuroscience undermines conscious willing concerns timing and appeals to the famous experiments of Benjamin Libet. Libet's experiments purport to show that the common perception that one's conscious will is decisive with respect to action is an illusion. Libel used a design in which subjects' scalps were monitored with electrodes while they were instructed to decide when to perform a minor motor action, such as raising a finger or pressing a button. Subjects were also positioned across from a device that allowed them to indicate when they had the sensation of a conscious willing. He found that a "readiness potential" that predicted action very well preceded the (reported) conscious willing by several hundred milliseconds. Libet argues that the conscious will does not initiate action (although he does think the will can veto action – we have a "free won't"). Professor Sinnott-Armstrong reviewed several follow-up studies that together with Libet's work suggest that the sense of conscious willing is an after-the-fact reconstruction, an epiphenomena and not a causally efficacious factor controlling action. He argued that the view that the conscious will is epiphenomenal does not undermine responsibility in general. The neuroscientific results concern minimal actions, un-thinking bodily movements that are not paradigmatic of action in general. However, some important and interesting cases do involve minimal actions (e.g. the case of State vs. Utter). In these and similar cases the neuroscientific results regarding the efficacy of conscious willing lend support to – and, more importantly, provide an explanation for – an excusing attitude that limits responsibility.
In sum, Professor Sinnott-Armstrong argued for an approach that denies that neuroscience can undermine responsibility in a general way, but affirms its relevance in particular contexts, depending on the type of action, the nature of the neuroscientific results, and the operative norms of holding people accountable.
Arnon Levy, Graduate Fellow in Ethics 2008-09