Some of you will know that I run a philosophy group. I am not a philosopher nor do I teach philosophy, but I provide a fortnightly opportunity for about a dozen people to discuss philosophy and philosophers. Surprisingly often the material from this group finds it way to this Blog, and vice versa. Some years ago I noted an interesting question which concerns the nature of identity. Here was what I wrote:
“My friend Joe is a skilled carpenter and boat builder. Some years ago he built a small rowing boat. Being a perfectionist his habit was to replace any part of the boat which was in the slightest damaged or worn. The first two or three planks he replaced gave me no philosophical difficulty – it was clearly Joe’s old boat with a few repairs.
But the day came when he had in fact replaced every single part of the boat. When I suggested that he had made a new boat with a different identity he denied this, saying: “The shape and length of every replacement piece has been dictated by the form of the boat so there has clearly been a continuity of identity because of the continuity of the form.”
But I had a better idea. Joe never throws anything away. When I looked under the tarpaulin at the back of the shed I found all the pieces and planks he had removed. So I put the old boat together again. Every part had to be put into the only place it could fit – the form was preserved. And I asked him to tell me whether the two boats shared the same identity. Joe is still scratching his head.
This is an old problem – it was originally Theseus’s boat, and the story comes to us through Plutarch. Nor is it academic, for the meaning of identity is important to us. I am told that throughout our lives the cells in our body, except in the neural cortex, die and are replaced – just like Joe and his boat. But if the body I have now has been replaced, cell by cell, a number of times, am I the same person? You might argue that the new cells, nevertheless inherit the same information. I hold in my memory the experience of being a child even if that memory is held in replacement cells.
Imagine that Hitler did not die in his bunker. He survived. But a nearby explosion permanently removed his memory from the age of 10 onwards. At his Nuremberg trial, the prosecution argued that he was clearly the same person who could properly be tried and punished. But the defence argued that it was plainly unjust to punish him for crimes of which he could have no knowledge. What would you decide?
And of course there is the knotty Catholic problem. In the matter of the real presence in the Eucharist we accept that the wafer before consecration has the identity of bread. The theologian distinguishes between substance – what it really is – and the accidents of that substance which we recognise through our senses. After consecration its substance, and therefore its identity, is radically changed but its accidents remain. No wonder that some theologians have looked for solutions in the concepts of symbol or sign. And the Lutherans hold that bread and wine body and blood coexist with each other. Yet such approaches do not appear to be an adequate response to Christ’s own description which emphasises the literality of the doctrine. Indeed, in John 6, he presents it as a challenge of faith to his listeners. It remains a challenge to us.