The Problem of Personal Identity

What is meant by “The Problem of Personal Identity”?

What is a person? What is it that makes us who we are? Is personality nothing more than our biology, or is the psychology of the inner-self something other than flesh and bone? And why should we care?

These questions are significant for at least at least two reasons: firstly, they are of paramount importance to religious believers who maintain—as do Buddhists, for example—that we are reincarnated (a significance which is highlighted in the ancient Buddhist quest for the soul, The Questions of King Melinda) and for Christians who believe in heaven—which, if true, is totally desirable. Secondly, they are of great importance to humans in general since the way in which we conceive the value of a human person invariably affects our ethical treatment of one another. If a human person is nothing more than a mass of tissue that ceases to exist at the moment of death then human experimentation, such as cloning, may not seem like such a pressing moral issue. On the other hand, if personal identity is intrinsically related to a Creative God to whom we are answerable at the end of life, then such ethical questions are considerably weightier.

David Chalmers of the Australian National University refers to these questions of human identity as ‘The Hard Problem of Consciousness’ and suggests that simple biology alone can not provide a total answer. There is, he suggests, something more to being human than what biology alone can account for: there is, for example, not just a sensation of pain, love and joy in the person but an experience of these things too. A machine, like a computer, can simulate a reaction to pain, but this does not count as an experience in the way a human experiences things. It is these experiences that seem to make up our personalities and to be something more than just physical flesh and blood.

John Locke, the 17th century English empiricist philosopher, took up this distinction in his Essay Concerning Human Understanding. Locke highlights the division between being ‘a man’ as flesh and blood and ‘a person’ as a source of identity in two thought experiments aimed at showing that the we typically identify personality with consciousness.

In the first thought experiment, Locke supposed that a parrot and a man had switched bodies. The physical man now could only repeat a few words mechanically, whereas the parrot—which assumed the man’s consciousness—was now a thinking, reasoning being with an sense of identity and a set of desires. Locke believes that this mind experiment clearly shows that we would consider the parrot to contain the ‘personality’ of the subject while the body simply contains ‘the man’. The distinction is underscored by the second thought experiment, which describes an educated and cultured prince whose consciousness enters and reanimates the dead body of an uneducated and unlettered cobbler; even though the prince is in a new body, he retains his love of culture and awareness of the world he had as a prince.

This is all well and good and on the face of it, Chalmers and Locke seem to have a strong case in favour of a non-material notion of personality—but in itself, showing a distinction between body and consciousness is not sufficient to count as a defence of belief in a Cartesian soul.

The Catholic theologian and founder of CTS publishing, Frank Sheed, in his book Theology for Beginners, tells a story of an argument he had one day with an atheist. “What is a soul?” asks the atheist; Sheed replies (and this is a paraphrase of the anecdote, not a direct quote), “A soul has no shape, no colour, no size and no weight and you can’t see it, feel it, touch it or smell it.” The atheist replies, “that’s the best definition of ‘nothing’ I have ever heard.” The story highlights the difficulty facing the theist (or at least the mind/body dualist): how to give a coherent account of an intangible entity? If there really is a distinction between consciousness and the body, what does ‘consciousness’ itself consists of? Surely not atoms, protons and quarks—but if it is nothing physical, what account can be given to satisfy us? Sheed's experience with the materialist in Hyde Park underscored for him the need for a substantial explanation of what an inanimate ‘soul’ actually is.

Chalmers and Locke may have successfully shown that there is a distinction between body and consciousness, but this distinction may be nothing more than a theoretical distinction. Gilbert Ryle, for example, who famously (and pejoratively) characterised Cartesian Dualism as being like the belief of a “Ghost in the machine” criticises theories which hold that the mind and body are separate entities as being a ‘Category Mistake.’ In a 1949 book called The Concept of Mind, Ryle draws a distinction between modes of talking and modes of reality. It’s one thing to talk about the mind as being an independent entity, but logically it is meaningless. In a sense, talk of a soul is mythological to help us make sense of difficult concepts, but the myth should not be confused for a literal explanation.

“A myth is…the presentation of facts belonging to one category in the idioms appropriate to another.” [The Concept of Mind]

While it is true that the problems raised by Ryle and characterised by the anecdote of Sheed are significant challenges for those who believe that personhood is tied up in something more than just the body, those challenges are not insurmountable. Peter Bertucci of Boston University for one provides a convincing argument that there is a very clear distinction between ideas and neurological realities. My ideas of beauty, for example, are not equivalent to the neurons that are produced in the brain. This distinction can not simply be dismissed as a ‘Category Mistake’. It is in fact logically necessary Bertucci maintains, that the idea of beauty is distinct from the mechanics of the idea of beauty (cf. Leibniz's Law of Indiscernibles). Mind is something other; the need for a fuller explanation does not diminish that reality.

“If the intellect is a physical body, it would have no knowledge of anything but bodies. But this is clearly false, since our intellect extends beyond the realm of phusical bodies. Hence, the intellect is not physical.”
[Thomas Aquinas, Summa Contra Gentiles, 2:49.5]