Page:Eddington A. Space Time and Gravitation. 1920.djvu/201

XII] yet learn "the game" in all its intricacy. Our knowledge of the nature of things must be like the antiquarians' knowledge of the nature of chessmen, viz. their nature as pawns and pieces in the game, not as carved shapes of wood. In the latter aspect they may have relations and significance transcending anything dreamt of in physics.

It is believed that the familiar things of experience are very complex; and the scientific method is to analyse them into simpler elements. Theories and laws of behaviour of these simpler constituents are studied; and from these it becomes possible to predict and explain phenomena. It seems a natural procedure to explain the complex in terms of the simple, but it carries with it the necessity of explaining the familiar in terms of the unfamiliar.

There are thus two reasons why the ultimate constituents of the real world must be of an unfamiliar nature. Firstly, all familiar objects are of a much too complex character. Secondly, familiar objects belong not to the real world of physics, but to a much earlier stage in the synthesis of appearances. The ultimate elements in a theory of the world must be of a nature impossible to define in terms recognisable to the mind.

The fact that he has to deal with entities of unknown nature presents no difficulty to the mathematician. As the mathematician in the Prologue explained, he is never so happy as when he does not know what he is talking about. But we ourselves cannot take any interest in the chain of reasoning he is producing, unless we can give it some meaning—a meaning, which we find by experiment, it will bear. We have to be in a position to make a sort of running comment on his work. At first his symbols bring no picture of anything before our eyes, and we watch in silence. Presently we can say "Now he is talking about a particle of matter"…"Now he is talking about another particle"…"Now he is saying where they will be at a certain time of day"…"Now he says that they will be in the same spot at a certain time." We watch to see.—"Yes. The two particles have collided. For once he is speaking about something familiar, and speaking the truth, although, of course, he does not know it." Evidently his chain of symbols can be interpreted as describing what occurs in the world; we need not,