2 July

Gravity and weight. All these weigh the same. But if you lift them they’ll feel lighter the bigger they get. Researchers tie themselves in knots trying to explain this. I haven’t seen anyone make the important point, that when you lift something, what you feel as ‘weight’ is not weight at all. Just as you can’t feel your own weight, you can’t feel the weight of another thing either. You can only feel the forces of interaction, between you and that other thing, whether it’s just the Earth, or a set of weights.