Normal human variation: refocussing the enhancement debate

Bioethics. 2015 Feb;29(2):133-43. doi: 10.1111/bioe.12045. Epub 2013 Aug 2.


This article draws attention to several common mistakes in thinking about biomedical enhancement, mistakes that are made even by some supporters of enhancement. We illustrate these mistakes by examining objections that John Harris has recently raised against the use of pharmacological interventions to directly modulate moral decision-making. We then apply these lessons to other influential figures in the debate about enhancement. One upshot of our argument is that many considerations presented as powerful objections to enhancement are really strong considerations in favour of biomedical enhancement, just in a different direction. Another upshot is that it is unfortunate that much of the current debate focuses on interventions that will radically transform normal human capacities. Such interventions are unlikely to be available in the near future, and may not even be feasible. But our argument shows that the enhancement project can still have a radical impact on human life even if biomedical enhancement operated entirely within the normal human range.

Keywords: enhancement; moral psychology; normal variation; status quo bias.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Biomedical Enhancement / ethics*
  • Citalopram* / administration & dosage
  • Citalopram* / adverse effects
  • Citalopram* / pharmacology
  • Decision Making / drug effects*
  • Decision Making / ethics
  • Emotions / drug effects
  • Emotions / ethics
  • Empathy / drug effects*
  • Empathy / ethics
  • Ethical Analysis
  • Ethical Theory
  • Genetic Enhancement / ethics
  • Human Characteristics*
  • Human Rights
  • Humans
  • Morals*
  • Nootropic Agents / administration & dosage
  • Nootropic Agents / adverse effects
  • Selective Serotonin Reuptake Inhibitors* / administration & dosage
  • Selective Serotonin Reuptake Inhibitors* / adverse effects
  • Selective Serotonin Reuptake Inhibitors* / pharmacology
  • Serotonin / blood


  • Nootropic Agents
  • Serotonin Uptake Inhibitors
  • Citalopram
  • Serotonin