Sir

I was somewhat bemused when reading your News Feature (Nature 419, 244–246; 2002). The view that “biology today is where physics was at the beginning of the twentieth century” misses a critical difference between the two disciplines. Biology has a grand unifying theory: it was published in 1859 by Charles Darwin as On the Origin of Species by Means of Natural Selection. The same cannot be said of physics, which continues to search for its theory of everything.