john_horgan's picture
Director, Center for Science Writings, Stevens Institute of Technology
We Have No Souls

This year's Edge question makes me wonder: Which ideas pose a greater potential danger? False ones or true ones? Illusions or the lack thereof? As a believer in and lover of science, I certainly hope that the truth will set us free, and save us, but sometimes I'm not so sure.

The dangerous, probably true idea I'd like to dwell on in this Holiday season is that we humans have no souls. The soul is that core of us that supposedly transcends and even persists beyond our physicality, lending us a fundamental autonomy, privacy and dignity. In his 1994 book The Astonishing Hypothesis: The Scientific Search for the Soul, the late, great Francis Crick argued that the soul is an illusion perpetuated, like Tinkerbell, only by our belief in it. Crick opened his book with this manifesto: "'You,' your joys and your sorrows, your memories and your ambitions, your sense of personal identity and free will, are in fact no more than the behavior of a vast assembly of nerve cells and their associated molecules." Note the quotation marks around "You." The subtitle of Crick's book was almost comically ironic, since he was clearly trying not to find the soul but to crush it out of existence.

I once told Crick that "The Depressing Hypothesis" would have been a more accurate title for his book, since he was, after all, just reiterating the basic, materialist assumption of modern neurobiology and, more broadly, all of science. Until recently, it was easy to dismiss this assumption as moot, because brain researchers had made so little progress in tracing cognition to specific neural processes. Even self-proclaimed materialists — who accept, intellectually, that we are just meat machines — could harbor a secret, sentimental belief in a soul of the gaps. But recently the gaps have been closing, as neuroscientists — egged on by Crick in the last two decades of his life--have begun unraveling the so-called neural code, the software that transforms electrochemical pulses in the brain into perceptions, memories, decisions, emotions, and other constituents of consciousness.

I've argued elsewhere that the neural code may turn out to be so complex that it will never be fully deciphered. But 60 years ago, some biologists feared the genetic code was too complex to crack. Then in 1953 Crick and Watson unraveled the structure of DNA, and researchers quickly established that the double helix mediates an astonishingly simple genetic code governing the heredity of all organisms. Science's success in deciphering the genetic code, which has culminated in the Human Genome Project, has been widely acclaimed — and with good reason, because knowledge of our genetic makeup could allow us to reshape our innate nature. A solution to the neural code could give us much greater, more direct control over ourselves than mere genetic manipulation.

Will we be liberated or enslaved by this knowledge? Officials in the Pentagon, the major funder of neural-code research, have openly broached the prospect of cyborg warriors who can be remotely controlled via brain implants, like the assassin in the recent remake of "The Manchurian Candidate." On the other hand, a cult-like group of self-described "wireheads" looks forward to the day when implants allow us to create our own realities and achieve ecstasy on demand.

Either way, when our minds can be programmed like personal computers, then, perhaps, we will finally abandon the belief that we have immortal, inviolable souls, unless, of course, we program ourselves to believe.