In the 1730s a Swedish botanist trudged through Arctic Lapland in an attempt to show that nature never changed. His journey was the first step in a trail that led through the Paris zoo, past an Oxford professor who ate mice and, among the shellfish under Mount Etna, to a new theory that proved the reverse: nature never stood still.The new theory finally broke the Church's power over science; it was seized on by the great political thinkers; and it gave us the modern world of constant change, where 'the newest survives' rules our lives.