Neuroscience and the Soul

Just spotted this letter published in the Feb 27 issue of Science. It addresses matters raised by non-materialist neuroscientists the Intelligent Design lobby about mind/body duality. I'm adding it here to my blog since this issue is one in which I am likely to participate in the future and so I would like to log as many instances of this "culture war" as possible. It is a hard task, but the logic of this letter is quite hard to refute in my opinion.

Neuroscience and the Soul

Science and religion have had a long relationship, by turns collegial and adversarial. In the 17th century Galileo ran afoul of the Church's geocentrism, and in the 19th century Darwin challenged the biblical account of creation. The breaches that open at such times often close again, as religions determine that the doctrine in question is not an essential part of faith. This is precisely what happened with geocentrism and, outside of certain American fundamentalist Christian sects, evolution. A new challenge to the science-religion relationship is currently at hand. We hope that, with careful consideration by scientists and theologians, it will not become the latest front in what some have called the "culture war" between science and religion. The challenge comes from neuroscience and concerns our understanding of human nature.

Most religions endorse the idea of a soul (or spirit) that is distinct from the physical body. Yet as neuroscience advances, it increasingly seems that all aspects of a person can be explained by the functioning of a material system. This first became clear in the realms of motor control and perception (1, 2). Yet, models of perceptual and motor capacities such as color vision and gait do not directly threaten the idea of the soul. You can still believe in what Gilbert Ryle called "the ghost in the machine" (3) and simply conclude that color vision and gait are features of the
machine rather than the ghost.

However, as neuroscience begins to reveal the mechanisms underlying personality, love, morality, and spirituality, the idea of a ghost in the machine becomes strained. Brain imaging indicates that all of these traits have physical correlates in brain function. Furthermore, pharmacologic influences on these traits, as well as the effects of localized stimulation or damage, demonstrate that the brain processes in question are not mere correlates but are the physical bases of these central aspects of our personhood. If these aspects of the person 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 than evolutionary biology to many religions. Predictably, then, some theologians and even neuroscientists are resisting the implications of modern cognitive and affective neuroscience. "Nonmaterialist neuroscience" has joined "intelligent design" as an alternative interpretation of scientific data (4). This work is counterproductive, however, in that it ignores what most scholars of the Hebrew and Christian scriptures now understand about biblical views of human nature. These views were physicalist, and body-soul dualism entered Christian thought around a century after Jesus' day (5, 6).

To be sure, dualism is intuitively compelling. Yet science often requires us to reject otherwise plausible beliefs in the face of evidence to the contrary. A full understanding of why Earth orbits the Sun (as a consequence of the way the solar system was formed) took another century after Galileo's time to develop. It may take even longer to understand why certain material systems give rise to consciousness. In the meantime, just as Galileo's view of Earth in the heavens did not render our world any less precious or beautiful, neither does the physicalism of neuroscience detract from the value or meaning of human life.

Martha J. Farah*
Center for Cognitive NeuroscienceDepartment of Psychology
University of Pennsylvania
Philadelphia, PA 19104, USA

*To whom correspondence should be addressed. E-mail: mfarah@psych.upenn.edu

Nancey Murphy
School of Theology
Fuller Theological Seminary
Pasadena, CA
91182, USA

References

1. M. Jeannerod, The Cognitive Neuroscience of Action (Wiley-Blackwell, Hoboken, NJ, 1997).
2. M. J. Farah, The Cognitive Neuroscience of Vision (Wiley-Blackwell, Hoboken, NJ, 2000).
3. G. Ryle, The Concept of Mind (Univ. of Chicago Press, Chicago, 1949).
4. M. Beauregard, D. O'Leary, The Spiritual Brain: A Neuroscientist's Case for the Existence of the Soul (HarperCollins, New York, 2007).
5. N. Murphy, Bodies and Souls, or Spirited Bodies? (Cambridge Univ. Press, Cambridge, 2006).
6. J. B. Green, Body, Soul, and Human Life (Baker, Grand Rapids, MI, 2008).