22 December to 5 January

The potential to change the world   Denis Rowley recently drew attention to the small social distances that separate human beings, while Tony Benn focused attention on the importance of encouragement. I confess that I gained nearly as much enjoyment from realising, on reading Denis's reflection, that I am only four handshakes from Barack Obama, as I do from knowing that though I am three handshakes from Nelson Mandela, Eric Clapton and John F. Kennedy, I am only two from Desmond Tutu, Muhammed Ali and R.D. Laing.

By focusing on the social networks in which we move, Denis Rowley reminds us that what we do has the potential to influence others - for good or for ill. Each act of kindness; every encouraging word, and every worthwhile step we help another person to take, has the potential to make the world a better place. Not only can we change her life for the better, but through our influence on her, however small, we can also impact on the lives of the innumerable others with whom she comes in contact. That is why we need to remember that each unkind act in which we engage and every discouraging word we utter, also has the potential to change the world.

Gavin Fairbairn, Running Stream Professor of Ethics and Language, School of Applied Global Ethics