THE UNIVERSE AND MATTER — LOUIS- JARAY 133 



accumulates until a certain quantity is stored up; when this quantity 

 is reached, the radiation is emitted. Thus the radiation emanating 

 from the atom is not considered as a continuous outpouring, but as a 

 discontinuous emission of grains. Innumerable experiments since 

 1900 have shown that this quantity, called a "quantum," is propor- 

 tional to the frequency of the radiation and not to its intensity. 

 Maurice de Broglie has invented an apparatus for measuring the veloc- 

 ity of corpuscles (electrons) torn away from matter by the action of 

 X-rays, which gives an experimental test of this "quantum" theory of 

 Planck. 11 Physics is thus thrown into confusion by the substitution 

 in the microscopic domain of the principle of discontinuity in place of 

 the principle of continuity. 



Leibnitz said that nature does not make jumps: Natura non facit 

 saltus; in the world of atoms, modern physics perceives nothing but 

 jumps. Atomic physics limits itself to uncovering the laws which 

 govern these jumps; it observes only the value, the quantum of energy; 

 it seeks to calculate the probability that an atomic system existing at 

 a given moment will find itself subsequently in such or such other 

 state; and atomic physics finds that these laws are only the laws of 

 probability. From the moment that one starts with the discontinuous 

 action of elementary corpuscles of matter and of light, one cannot 

 know whether at a given moment one of these corpuscles has or ought 

 to have a certain precise position in space or a certain strictly defined 

 motion; atomic physics declares it is impossible "to predict the future 

 motion of a corpuscle of an atom." Indetermination is substituted for 

 determinism; it is the "constant h" of Planck, the "uncertainty prin- 

 ciple of Heinsenberg." All the experiments relative to "quanta" for 

 30 years are affected by an unknown, an indeterminate element that 

 must be introduced to make the calculations succeed. This indeter- 

 minate constant has been represented by h, and it is even to this day 

 susceptible of no interpretation. All the determinism of the mechanics 

 of Newton is thus as if undermined at its base. "The significance (of 

 this constant)," says Louis de Broglie, "has been for 30 years and still 

 is today the enigma of modern physics ; it has remained the undefinable 

 syllable in nature's cross-word puzzle." This fundamental indeter- 

 minism appears as a sort of free choice of nature, escaping thus from 

 the rigorous law of mechanics. 



It is scarcely necessary to add that this introduction of discontinuity 

 and indeterminism into physics is valid for the whole universe; but 

 the indeterminate constant, represented by h in the calculations, is 

 very small. Consequently, in the phenomena having to do with man 

 or the stars, it is negligible. A margin of uncertainty always exists, 

 but since it is less than the unavoidable errors which affect all observa- 



11 Vie et transmutation des atomes, p. 164; the application of this eflect called "photoelectric" is utilized in 

 television and in moving picture talking films. 



