Jay asked:

Does a cloned human have soul?

Answer by Geoffrey Klempner

Do souls exist? Do you have a soul? How do you know?

Descartes gave a famous argument for the soul: I know that I would exist, even in a possible world where there is no material objects or space. I ‘see’ my own soul, my own existence, in a way which is totally different from the way I ‘see’ external things. My soul is immediately present to me, in a way which cannot possibly be subject to deceit or illusion.

Descartes ‘knows’ that he has a soul. What would Descartes say about the cloned copy of Descartes? Descartes has a clear answer to this: The behaviour of human beings and non-human animals is fundamentally different in character. Non-human animals are just biological machines. Their behaviour can be fully explained by the activity of neurons, nerves, sinews, muscles. Human beings, by contrast, have the capacity for judgement and choice. This, Descartes believed, requires a non-physical, non-mechanical input: a soul which does the judging and choosing, transmitting its impulses to the physical body through a mind-body bridging mechanism (which for obscure reasons Descartes believed to reside in the pineal gland).

It follows that the cloned copy of Descartes must have a soul. This is assuming that it behaves in the way a human being behaves. If Descartes’ clone can debate philosophy with Descartes, then the two individuals are perfect twins in every respect, physical and non-physical. (How the cloned copy ‘received’ its soul is a mystery that need not delay us.)

Descartes’ model for animal behaviour was clockwork automata, which by this time had reached a remarkable degree of sophistication — for example, lifelike ‘birds’ twittering in cages. Despite this, the materialist Hobbes took a radically different view: we can’t know for sure that the brain does not work in a similar way, if you make the ‘clockwork’ sufficiently complex.

Sound familiar? The very same debate is taking place today, only with the allegedly more fertile model of computers (Turing machines) or neural networks replacing clockwork. One can only guess at the outcome of this ongoing debate.

To cut a long story short: it is logically possible that there is such a thing as a soul, which is required in order to be fully human. A cloned copy of you or me might, or might not have a soul, but there would be, in principle, a way of testing this. Perhaps a soulless ‘zombie’ clone could perform simple mental tasks, but fail at more complex tasks requiring imagination. (There’s a nice illustration of this at the end of the comedy movie Shaun of the Dead (2004) — I don’t want to give away any spoilers.)

However, there is another thought which runs counter to this. Maybe, the debate about computing and consciousness will be resolved in favour of the materialist response. A cloned copy of you or me would be physically identical in every respect, not lacking any mental capacity possessed by the original. What is scary about this is that your best friend could be a soulless zombie and you would never know.

Does that make sense? I am not sure that it does. Let’s say that I believe that there could be, in principle, an indistinguishable cloned copy of me which lacked a soul. For my cloned copy, ‘all is darkness inside’. However, if I believe in the possibility of a soulless cloned copy, then my cloned copy must ‘believe’ this too. That is to say, it must act in every way ‘as if’ it ‘believes’ that it has a soul. What is the evidential basis for this belief? The same as the evidential basis for my belief!

Something very wrong is going on here. Everything I say and do, including all my talk of ‘having a soul’ is fully accounted for at the physical level. That suggests strongly, to me, that such a belief would indeed be illusory.