Alien Hand Syndrome: Ethical Issues


At the nexus of theories of mind and the science of the brain is alien hand syndrome, a rare neurologic disorder in which one hand displays complex nonvolitional behaviours. The causative lesion disconnects brain regions that initiate hand movement from those needed for conscious recognition of volition. The aberrant behaviours may be unwilled and automatic, or in other cases they may be unconsciously willed yet unrecognised as the patient's own. Although sometimes touted as proof that free will does not exist, scientific descriptions of alien hand phenomenon are neutral in regard to competing philosophical theories attributing human decision to free agency or to determined physical processes. How one thinks about the nature of free will is important for ethics, which respects the validity of personal autonomy in moral decision making. Demonstration that some purposeful actions may be unwilled does not mean that all thoughts are predetermined. Therefore, neuroscientific explanations of alien hand syndrome can help to inform but do not dismantle traditional approaches to biomedical ethics.

Key Concepts:

  • Alien hand syndrome is a neurologic condition in which the affected hand exhibits complex nonvolitional behaviours.

  • It results from disconnection of brain regions that control the hand from those that signal conscious recognition of volition.

  • Other clinical examples of complex involuntary behaviours are recognised.

  • Purposeful yet nonvolitional behaviour calls into question common understandings of free will.

  • If no human decisions were freely made, then the ethical principle of respect for autonomy would be meaningless.

  • Personal culpability for unwilled harmful actions is ethically and legally diminished.

  • Just because some actions may be unwilled does not mean that all are.

  • Scientific accounts of alien hand syndrome are philosophically neutral with respect to theories of agency versus determinism.

  • Some instances of alien hand syndrome may be a form of agnosia of agency.

Keywords: alien hand syndrome; free will; autonomy; automatism; mind brain problem


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Cheshire, William P(Aug 2012) Alien Hand Syndrome: Ethical Issues. In: eLS. John Wiley & Sons Ltd, Chichester. [doi: 10.1002/9780470015902.a0024158]