Originally published in Italian in 1976, this book describes the methods scientists use to investigate the physical world. It is ideal for students and teachers of science and the philosophy of science. It is both a high-level popularization and a critical appraisal of these methods, describing important advances in physics and analyzing the historical development, value, reliability and philosophical implications of the way physicists approach the problems confronting them. The introductory chapter on the meaning of physical theories and the mathematical tools used to develop them is followed by a general discussion on the foundations of physics under four major headings: the physics of the reversible, the physics of the irreversible, microphysics, and cosmology. Throughout, the subject matter of physical theories is linked to discussion of the attendant philosophical and epistemological implications, such as the validity of the theories, inductive inference, causal explanation, probability, the role of observation and the reality of physical objects.
Prefaces; Part I. The Method of Physicsphysics?; 3. A first approach to the method; 4. The value of the method; 5. The operational definition; 6. The language of physics; 7. Observables or theoretical constructs?; 8. How many physical quantities are there?; 9. The precision of measurements; 10. The limits of the validity of a physical law; 11. The procedure of classical physics; 12. The mathematical functions used in physics; 13. The units of measurements; 14. The dimensions of physical quantities; 15. Theories, hypotheses, models; Part II. The Physics of the Reversible: 1. The divisions of classical physics; 2. Velocity and acceleration; 3. Curvilinear motion; 4. The laws of dynamics; 5. Work and energy; 6. The invariants; 7. Action at a distance; 8. Do magnetic charges exist?; 9. The field concept; 10. Electromagnetism; 11. Maxwell's equations; 12. The electromagnetics waves; 13. The polarization of material media; 14. Reflection, refraction, dispersion; 15. Lenses and images; 16. The physical theory of vision; 17. How do we really see?; 18. Interference and diffraction; 19. The Galilean relativity; 20. Einstein's relativity; 21. The Lorentz transformation; 22. Length contraction and time dilation; 23. The limiting velocity, the past and the future; 24. The invariance of the laws of physics; 25. Gravitation; 26. General relativity; 27. Consequences of general relativity; 28. Physical theories; 29. The richness of the man-nature relation; Part III. The Physics of the Irreversable: 1. Reversability and irreversability; 2. Temperature and heat; 3. Perfect gases; 4. Heat, work, and internal energy; 5. Specifics of a heat gas; 6. The second law of thermo dynamics; 7. The entropy; 8. The nonlinear development of classical thermodynamics; 9. The kinetic theory; 10. Probability; 11. Information; 12. Information and probability; 13. The transmission of informations; 14. Microstates and macrostates; 15. Statistical irreversability; 16. Does time have an arrow; 17. Fluctuations; Part IV. Microphysics: 1. The objects of physics; 2. Spectral lines; 3. Electrons; 4. Classical models of the atom; 5. Planck's quanta; 6. Photons; 7. The Bose-Einstein statistics; 8. Bohr's atom; 9. Waves and particles; 10. The probabalistic interpretation; 11. Spin, atoms and molecules; 12. Bosons, fermions, antimatter; 13. The uncertainty principle; 14. The Hilbert space; 15. The formalism of quantum mechanics; 16. Revision of the general scheme of physics; 17. Difficulties of quantum mechanics; 18. Microphysics and reality; 19. Determinism and indeterminism; 20. Causality; 21. The inductive inference; 22. Quantum electrodynamics; 23. The atomic nucleus; 24. The second crisis of classical physics; 25. Particles multiply; 26. Interactions and conservations; 27. Toward the grand unification; 28. Materialism and mechanism in contemporary physics; Part V. The Universe: 1. General laws and historical facts; 2. Form and movements of the earth; 3. The earth's structure; 4. The cosmogonic problem; 5. The environment and the biosphere; 6. The origin and evolution of life; 7. Windows on the universe; 8. The solar system; 9. The origin of the solar system; 10. The stars; 11. Neutron stars, pulsars, blackholes; 12. The galaxies; 13. Cosmological hypotheses; 14. Life in the universe; Notes; References; Indices.