Oppenheimer Sees Problem Of Definition

We are limited in our description of any phenomenon by our very civilization, by tradition, and by words which are conditional and limited, J. Robert Oppenheimer '26 told a Sanders Theatre audience yesterday in the fourth talk of a series entitled "The Hope of Order." The atomic scientist said that we must continually search for descriptions which encompass and transcend the descriptions of the past.

Oppenheimer spent most of this William James Lecture discussing a pertinent example from his own field. He explained that although in physics "we have all the breaks," the lesson learned from the example he cited might show the way to how the problems of redefinition might arise and how man may cope with them.

The great clash between Newtonian mechanics and atomic theory which developed around the turn of the century provided an excellent example of the continual need for transcending existing concepts and definitions, he said.

Oppenheimer explained that the contradictions at the atomic level occurred over these questions: 1) how does matter move and what are the forces at work on it; 2) what is the nature of light; and 3) how can one define the atom.

Considering the first topic, Oppenheimer pointed out that Newtonian mechanics had been enormously successful in application to the effects of gravitational forces, but they were unable to explain the constant shape and, in general, size of the electon orbits.

In the area of the nature of light, the conflict between light's wave and quantum nature was cited as another example of the clash between the traditional and the newly discovered. After Huygens' enunciation of his famous Principle, the whole question of light's nature and propagation appeared settled. But Planck's theory of the quant of light energy, as elaborated by Einstein, threw the classical conceptions into serious problems.

Finally, the atom's very shape and nature was at once elucidated and complicated by Rutherford's experiments and Bohr's subsequent theory of the hydrogen atom. The idea of agitated orbital states, defined in integral multiples of Planck's constant seriously contradicted the vision of classical mechanics