Neuroscientists believe that they have discovered a biological basis for morality. If certain brain cells are knocked out with an aneurism or a tumour, the ability to think straight about some issues of right and wrong is permanently skewed. "It tells us there is some neurobiological basis for morality," said Harvard philosophy student Liane Young, who helped to conceive the experiment.

The neuroscientists studied people who had injured an area that links emotion to cognition which is located in the ventromedial prefrontal cortex several inches behind the brow. When they were asked to consider hypothetical moral dilemmas which involved taking one life to save others, they felt no compunction whatsoever.

The experiment highlighted the importance of unconscious empathy and emotion in guiding decisions, the scientists contend. "When that influence is missing," said University of Southern California neuroscientist Antonio Damasio, "pure reason is set free."

This suggests to Harvard neuroscientist Marc Hauser that the brain is hard-wired for morality. He says that most moral intuitions are unconscious, involuntary and universal, based on surveys of thousands of people in hundreds of countries. He feels that this may proves a shared innate capacity for morality.

While this might sound comforting to some moralists, it could become a revolutionary concept if it were linked to ethical theories which argue that humans are destined to transcend their biology. What if we could transcend our biological revulsion at assassination or suicide bombing? It could be very useful to certain groups.