I am fortunate that my life has been a happy one. Now retired, my days still fill with simple pleasures, a favourite of which are walks with my wife Lek, our still-growing family, and my whippet. Lek and I treasure above all else these times spent with our family. But I am now getting close to the end of my life. This prospect does not trouble me greatly even though, as a scientist, I discounted long ago any supernatural explanation of life in favour of one based on natural forces, including evolution, genetics, and heredity. My own genetic make-up, inherited from my parents and theirs, has already been passed to our children and grandchildren in that cycle from birth to birth that bypasses death. Although I am saddened to think that my death may cause my family grief, they will surely be comforted knowing as they walk away from the grave, that they together represent more of me than lies behind. And they will know that I loved them each and that their company was my greatest pleasure. I find immense comfort also in knowing that the same ties of heredity binds us to all life on earth, in all its various forms. We must therefore be kind, and look after each other.

Looking towards my final days, I want to avoid that greatest of all indignities and distresses, of declining into mental confusion and helplessness. If that seems likely I have planned a merciful end to my own happy life.