When I was at CERN in 1974, one door in the theoretical physics division was always open, more often than not revealing its occupant leaning back in his chair, hands on head, feet on desk, with eyes closed. This was John Bell, thinking about quantum mechanics. All physicists come into contact with quantum physics and its profound depths. A famous cartoon shows a sad figure slumped in the corner of the laboratory, while one professor tells a visitor: ‘That’s X; brilliant mind but he tried to understand quantum mechanics.’ I, like many, decided that if the likes of Einstein, Bohr and Bell had not come to an agreed opinion, there was little point in me trying to do anything other than use its equations without worrying what it all meant.

That is the approach that most adopt, in some cases with considerable success. My own recent book, The Infinity Puzzle, tells how quantum field theory in the 1970s led to a successful description of physical reality and the current idea that an understanding of the origins of the material universe