The claim that human beings have an immoral soul is certainly ancient.  It is clear that Plato’s dualism was built on the foundation of Socrates’ belief in immortality and possibly reincarnation.  In addition, evidence from the Bible suggests that belief in an immortal soul predated Christianity – though the belief is not represented consistently in the Old Testament – and became increasingly important as hopes for an immanent eschaton faded with the 1st Century. Further, the idea that personal identity can survive trauma, aging and ultimately death fits with human experience and supports both morality and hopes for life after death which many of us want if not need to maintain.  Nevertheless, despite the persistence and appeal of these beliefs, claims that human beings have immortal souls lack credibility in the 21st Century.

Firstly, as Aristotle observed, “the soul is inseparable from its body” [On the Soul, Book II] He used the analogy of wax and a seal impression to make his point, writing “we must no more ask whether the soul and body are one than ask whether the wax and the figure impressed on it are one.” [Aristotle “Psychology” translated by E. Wallace, p. 61, 1882]  While he accepted that human beings have PSYCHE, and that these come in three parts, unlike his teacher Plato, Aristotle rejected the idea that this could ever be separated from the body or survive death.  As Brian Davies OP has noted, just because I consider myself to be sober doesn’t mean that I am. The fact that I feel separated from my body doesn’t mean that I am.  GEM Anscombe agreed, arguing that the feeling of having a separate soul is not a proper argument for the soul’s separability.  Further, as Gilbert Ryle suggested, the soul is the product of the parts and functions of the body operating together.  When we speak of “the soul” it is much like speaking of “the university” in Oxford or “team spirit” in cricket… these things are an undoubtedly part of our experience, but they cannot be separated from the components which make them up.  As Ryle wrote in “The Concept of Mind” (1949) Chapter 1, belief in a separate, separable and possibly immortal soul is the result of “that a family of radical category mistakes”… continuing, this “is the source of the double-life theory. The representation of a person as a ghost mysteriously ensconced in a machine derives from this argument”. To claim that human beings have separable souls, which – not least given our certain scientific knowledge that bodies decompose – is a precondition of having immortal souls, is to build assumptions on top of gut feelings in spite of the evidence, to make a “category mistake” and to take what is essentially a metaphor literally.  

Secondly, as Richard Dawkins has argued, the theory of evolution can account for the impression of consciousness which contributes to the claim that human beings have immortal souls.  In The Selfish Gene (1976) he wrote “we are survival machines – robot vehicles blindly programmed to preserve the selfish molecules known as genes.” In 1993 he speculated that the impression of consciousness and a separate soul has become an essential part of being human because it confers a survival advantage to our genes, suggesting that “brain hardware has co-evolved with the internal virtual worlds that it creates. This can be called hardware-software co-evolution.” The Evolutionary Future of Man (1993)  Dawkins’ reductive materialism is supported by the famous case of Phineas Gage, who suffered a traumatic brain injury and then experienced a complete transformation of personality and identity as a result.  The mind, consciousness or “soul” is nothing more than the impression given off by the normal operation of the brain.  Change the brain, change the “soul”.  Kill the brain, destroy the soul.  Basic biology shows that the soul is far from being immortal and that any claim that human beings have an immortal soul lacks credibility in the 21st Century. 

Further, Peter Geach agreed with the evolution argument, arguing that human beings are sophisticated animals and that our belief that we are somehow different is no more than “savage superstition” [God and the Soul (1969),quoted by John Haldane in Anscombe and Geach on Mind and Soul (2016)].  It is undoubtedly convenient that human beings claim to have a “soul” where other – genetically similar – animals do not.  For Christians, the existence of the soul explains the unique connection between human beings and God, in whose Image they are made.  Further, the existence of a soul both justifies our preferring members of the species homo sapiens in moral decision-making and supports the religious principle of the Sanctity of Human Life.  If human beings have no separable soul or any claim to immortality then it becomes more difficult to justify decisions which ignore the claim of tribes of orangutans on Indonesian rainforests or which deprive blue whales of their habitats for the benefit of a few human capitalists with financial interests in palm oil or Krill.  As far back as the 18th Century Immanuel Kant highlighted the importance of believing in immortality for moral philosophy.  As he argued, without believing in God, freedom and immortality it would be impossible to explain our duty to follow the moral law as there would be no reason to suppose that the law which appeals to us has authority, that we have the ability to do what we feel called to do or that there could be any ultimate point in doing so.  Without the possibility of immortality, which the separable soul supports, there is little reason to do what is right in a world where goodness is rarely rewarded in this life.  Nevertheless, the undesirability of the alternative conclusion is not a proper argument for the existence of an immortal soul in human beings, so the claim that human beings have an immortal soul lacks credibility.  

Clearly, there are arguments in favour of dualism.

Plato used his famous slave-boy in the Meno to argue that we have memories of the forms, either from past lives or from our soul’s previous home in the world of the forms, which best explain our ability to “learn” mathematics and logic quickly.  For Plato, learning is really remembering.  Today, Noam Chomsky’s work on language acquisition makes this idea more interesting  than it might have seemed a few decades ago, however even nativist accounts of language and research evidence indicating that the human brain is somehow “hardwired for language” does not take away from the possibility that this hard wiring could be explained by evolution, without the need to hypothesize the existence of an immortal soul.  

In addition, Descartes built on Plato’s scepticism about sense-data, pointing out the many ways in which the evidence of eyes and ears turns out to be mistaken.  A stick put in water surely does appear to bend.  Nevertheless, Descartes’ radical conclusion, that the only thing of which I can be certain is “cogito ergo sum” seems to go well beyond the evidence.  In 1968 Norman Malcolm poked holes in Descartes reasoning on a technical level, however even in the most obvious way it is apparent that while the senses do lie, conceptual analysis just as often deceives us.  As Aristotle himself pointed out, “if, then, a man has the theory without the experience, and recognizes the universal but does not know the individual included in this, he will often fail…” [Metaphysics Book 1:1]  Further, Descartes’ arguments for substance dualism, with the seat of the soul in the Pineal Gland, can only in the light of 21st Century science, be seen as uninformed speculation.  Descartes is far from being justified in his conclusion that “it is certain that I am really distinct from my body and can exist without it.” [Meditations Book VI, 54] and the claim that human beings have an immortal soul continues to lack credibility.  

Finally, paranormal experiences and particularly Near Death Experiences have been used to support claims that human beings have immortal souls.  For example, in 1991 American singer-songwriter Pam Reynolds had a powerful experience of being separated from and looking down on her body and of spending time in “heaven” during a stand-still operation for a brain aneurism.  Nevertheless, most of these experiences fail to stand up to careful scrutiny.  Susan Blackmore described her own journey to this realisation, writing

“It was just over thirty years ago that I had the dramatic out-of-body experience that convinced me of the reality of psychic phenomena and launched me on a crusade to show those closed-minded scientists that consciousness could reach beyond the body and that death was not the end. Just a few years of careful experiments changed all that. I found no psychic phenomena—only wishful thinking, self-deception, experimental error and, occasionally, fraud. I became a sceptic” The New Scientist (2000)

Further, those experiences which resist explanation in simple physiological or psychological terms, such as those highlighted by Dr Sam Parnia in his Aware and Aware II studies, are few in number and may still be explained by scientific progress.  Just because we cannot explain a few experiences with current scientific models doesn’t give us a reason to ditch scientific materialism and regress to a primitive dualistic world view predicated on supernatural entities for which there is no evidence.  

In conclusion, the claim that human beings have immortal souls lacks credibility in the 21st Century.  While the claim speaks to the experience of being human and supports the convenient belief that human beings are ontologically different from animals, there is no proper evidence or sensible argument to support substance dualism.  Those with religious faith will, of course, continue to make the claim that human beings have immortal souls.  The claim is central to their world-view and it is difficult to imagine how Christianity in particular could function without it.  Yet in making the claim believers emphasize how far in faith they are willing to stray from what can be supported through evidence and argument.

Bibliography

• Class Notes on Soul, Mind & Body
• Gilbert Ryle “The Concept of Mind” Chapter 1
• Susan Blackmore “Consciousness: An Introduction”