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Machine morality: bottom-up and top-down approaches for modelling human moral faculties


The implementation of moral decision making abilities in artificial intelligence (AI) is a natural and necessary extension to the social mechanisms of autonomous software agents and robots. Engineers exploring design strategies for systems sensitive to moral considerations in their choices and actions will need to determine what role ethical theory should play in defining control architectures for such systems. The architectures for morally intelligent agents fall within two broad approaches: the top-down imposition of ethical theories, and the bottom-up building of systems that aim at goals or standards which may or may not be specified in explicitly theoretical terms. In this paper we wish to provide some direction for continued research by outlining the value and limitations inherent in each of these approaches.

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An earlier version of the paper was prepared for and presented at the Android Science Cog Sci 2005 Workshop in Stresa, Italy. We wish to thank Karl MacDorman, coorganizer of workshop, for his encouragement, detailed comments, and editing suggestions. We are also grateful for the helpful comments provided by three anonymous reviewers arranged by the Workshop organizers.

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Correspondence to Wendell Wallach.

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Wallach, W., Allen, C. & Smit, I. Machine morality: bottom-up and top-down approaches for modelling human moral faculties. AI & Soc 22, 565–582 (2008).

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  • Moral Judgment
  • Moral Reasoning
  • Emotional Intelligence
  • Virtue Ethic
  • Ethical Theory