Most people are Cartesian dualists: they believe that body and mind are distinct. Until recently, neuroscience did not pose a strong challenge to this view. Revealing the neural mechanisms of color vision puts color vision in the realm of the body, as opposed to the mind, but so what? You can still believe in what Arthur Koestler called “the ghost in the machine” and simply conclude that color vision is carried out by the machine for the benefit of the ghost.

However, as neuroscience begins to reveal the mechanisms of personality, character, and even sense of spirituality dualism becomes strained. If these are all features of the machine, why have a ghost at all? By raising questions like this, it seems likely that neuroscience will pose a far more fundamental challenge to religion than evolutionary biology.

Martha J. Farah