Many things in Nature which we thought to be eternal, like the fixed stars, atoms, or quantities such as mass, turned out to be only temporary forms. Now the only thing which is believed to be of eternal stature is the law of Nature. In a contribution to a symposium at the Pontifical Academy of Science on ‘Understanding Reality: The Rôle of Culture and Science’ I tried to explain why I do not think that this is necessarily so and that also the laws may evolve in the course of the history of the universe. Herewith I would like to submit this heresy to a wider scientific public, not as an eternal truth but as a possibility worthy of reflection and discussion.

Today physics knows the laws which describe the material world from the tiny to the vast. That there are no phenomena known which contradict these laws is small wonder since whenever this happened, physics had to adjust them to accommodate also the hitherto unexplained events. The surprising fact is that in this process of gradual extension the laws became both more general and more unified. For instance, quantum mechanics of atomic systems supersedes classical mechanics and incorporates it as a limiting case. Similarly, elementary particle physics contains atomic physics as a low energy limit. This leads people to think that at the top of this pyramid there is an Urgleichung (as it was termed by Heisenberg; now it is called a TOE = Theory of Everything) which contains everything.