Saturdays are precious. In the monastery we don't usually do anything different from what we do on other week-days, but we sense the general air of relaxation that fills the village and, if we have no groups in, try to find time for a longer walk in the early morning. The Downs are empty, save for the occasional rider. The sky stretches overhead and the only sounds are natural ones, birds and small animals for the most part, with the hum and whip of the wind a constant backdrop. It's an excellent time and place for thinking and the past week has provided much to mull over. Dare we hope that President Obama's acknowledgement that nuclear warfare belongs to the past is going to resonate with the rest of the world's leaders? Or must we fear that the revelations about Iran's nuclear programme are going to cast a long shadow over the future? We are not far from Harwell, the name of which is virtually synonymous with the UK Atomic Energy Authority (although it is now also associated with a range of hi-tech research projects including those of the European Space Agency and Diamond Light Source). Looking down from the Ridgeway at the Harwell campus, one experiences a curious mix of hope and fear: hope that so much effort and ingenuity will result in great benefits, and a nagging fear that it could all go so horribly wrong. We know the men who first split the atom had reservations about the consequences. It is difficult to forget them this morning. The larks and the lapwings that so delight the Saturday morning visitor to the Downs are in decline, and it seems to be because of our careless stewardship of the earth. Folly is not only a great sin, it is dangerously easy to fall into.