The New Conceptualization Required in the New Physics
SUMMARY: We have seen that classical physics, by developing a method of describing (a part of) experience quantitatively, improved upon our common-sense world picture, but remained closely linked with it conceptually. Now while success over the millennia guarantees the essential adequacy of this conceptualization scheme at the macroscopic level, there is no a priori reason for it being equally successful in dealing with phenomena outside the regions accessible to man's unaided senses. In Chapter 4 we investigated a number of these phenomena that were contradictory and inexplicable in Newtonian Mechanics and in the next chapter we examined part of the semiotic of the new theories, Relativity Theory and Quantum Mechanics, developed to cope with this new experience. Both of these theories use the same observables as those of the classical theory: position, momentum, energy, etc. In contrast, however, to the classical theory whose structure is such that (in principle) its predictions are of the form: at time 't', the value of the observable quantity 'a' will be 'a1'; we have seen that a typical Quantum Mechanics prediction would be: at time 't', the possible values that will be obtained in a measurement of 'a' are 'a1', 'a2', 'a3'. . . etc., and the probability of getting 'a1' is 'P1', of getting 'a2' is 'P2', etc. (The sum of the probabilities, ΣPi, must of course be 1, because, if a measurement is carried out, some answer 'ai' must be obtained.) Since no mechanism exists inside Quantum Mechanics permitting unique predictions of the classical deterministic type, we are up against a radically new sort of physical theory and a new conceptual world picture seems to be required.
The rather ascetic nature of Quantum Mechanics and its 'renunciation of a more complete and precise description of experience' has rendered it unpalatable to a number of physicists and philosophers. These feel that the essence of a satisfactory scientific theory lies in its ability to make deterministic predictions. For them, any theory unable to do this is of only interim value, and is due for revision as our knowledge and techniques advance. The psychological origin of their beliefs, rooted in the up-to-yesterday successful common-sense--classical physics world pic-