Laying my cards on the table, I'm someone who doesn't believe in any god or mystical force or being - and I equally do not believe in life after death. Some think that the idea that we simply come into being as a bunch of cells - albeit highly complex cells - and then wink out of existence as we die is a disturbing thought. Surely it is so much more comforting to think that we live as part of a great cycle of life.

No, I would bluntly respond. To think that I am part of some act of creation, and that our 'soul' can be transferred into another body is a puzzling one. It is our physical make-up that shapes what we are. We are not dual beings, with a soul and a body coexisting for a time, and then the soul moving on into another body. We are our bodies, pure and simple. Our desires, our appetites, our sense of ourselves, derive from our physical shells. I think it is an amazing thought that organisms on earth have developed into such complex beings that one single example of life on earth, us, can think in such complex ways and have such a great sense of ourselves.

I see no mechanism by which reincarnation could occur. How is the soul stored, how does it travel? And then, what does it mean to say that a soul that was once in one body is now in another? It would mean that we are merely the host of something that is not 'us' and I find that hard to comprehend. All of our feelings, desires, impulses, reflexes and emotions can be explained by evolutionary theory. As time has gone on, diversity, selection and chance has played a role in creating the complex being that we are. What on earth does it mean to say we superimpose a pre-existing soul on this already complex being?

But my objection to reincarnation comes down to the fact that it requires a deus ex machina - something which I cannot accept. There is surely no other way to explain away the existence of reincarnation. Our souls are contained in our bodies and, principally, in our brains. When we die, our cells break down as the body is destroyed. Amazing as it may seem, the soul dies then too, because all the soul ever was was a complex set of electrical and chemical signals. And I find that an uplifting thought, not a depressing one.