What is physics?
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Abstract
‘Physics deals with those phenomena of the inanimate world which do not produce deep changes in the structure of matter’ the old schoolbooks said. In modern terms this would mean that classical physics restricted itself to phenomena t room temperature which modified only the secondary intermolecular bonds in condensed matter, i.e. the energy concentration is supposed to be smaller than 1 eV per atom. ‘Chemistry deals with those phenomena of the inanimate world which imply essential change in the structure of matter’. The Bunsen flame is the symbol of chemistry. Chemists play with fire: they concentrate several electron volts on a molecule because they intend to rearrange its covalent bonds. ‘Astronomy works with celestial objects’. Note the difference between observation nd experiment, between observatory and laboratory. ‘Biology investigates living entities’. The saturating valence appeared to be qualitatively different from the force of a spring. In the last century no one asked what was a part of physics, what of chemistry. Pasteur proved that a living being can descend only from other living ones. The elusive vis vitalis made a sharp distinction between lifeless and living. But we now understand that these boundaries were never impenetrable, rather they were unexplored frontiers separating the territories of science. The revolutionary 20th century had no respect for traditions either in society or in science. The pioneers of modern physics entered the terra incognita without inhibitions. They solved the puzzle of the H2 molecule, explored the centre of the sun, redesigned the atomic nucleus and now they are busy mapping the depths of the proton. They created tools to explore the alpha helix of protein and the double helix of genetic material. The wide strips of the terra incognita shrank to small white spots between the different branches of science. The real challenge for the coming generation is a great universal unknown surrounding our knowledge, stretching towards the infinitely small, infinitely large and infinitely complex . . .