MODERN PHYSICS JEANS 85 



starting points. But the existence of this matter was a pure hypothe- 

 sis; and matter is in actual fact as unobservable as the ether, New- 

 tonian force, and other unobservables whicli have vanished from 

 science. Early science not only assumed matter to exist, but further 

 pictured it as existing in space and time. Again this assumption 

 had no adequate justification; for there is clearly no reason why 

 the whole material universe should be restricted to the narrow 

 framework along which messages strike our senses. To illustrate 

 by an analogy, the earthquake waves which damage our houses 

 travel along the surface of the ground, but we have no right to 

 assume that they originate in the surface of the ground; we know, on 

 the contrary, that they originate deep down in the earth's interior. 



The Newtonian mechanics, however, having endowed space and 

 time with real objective existences, assumed that the whole universe 

 existed within the limits of space and time. Even more character- 

 istic of it was the doctrine of " mechanistic determinism ", which 

 could be evolved from it by strictly logical processes. This reduced 

 the whole physical universe to a vast machine in which each cog, 

 shaft, and thrust bar could only transmit what it received, and wait 

 for what was to come next. When it was found that tlie human body 

 consisted of nothing beyond commonplace atoms and molecules, 

 the human race also seemed to be reduced to cogs in the wheel, and 

 in the face of the inexorable movements of the machine, human effort, 

 initiative, and ambition seemed to become meaningless illusions. 

 Our minds were left w^ith no more power or initiative than a sen- 

 sitized cinematograph film; they could only register what was 

 impressed on them from an outer world over which thej^ had no 

 control. 



Theoretical physics is no longer concerned to study the Newtonian 

 universe which it once believed to exist in its own right in space and 

 time. It merely sets before itself the modest task of reducing to 

 law and order the impressions that the universe makes on our senses. 

 It is not concerned with what lies beyond the gateways of knowledge, 

 but with what enters through the gateways of knowledge. It is con- 

 cerned with appearances rather than reality, so that its task resembles 

 that of the cartographer or mapmaker rather than that of the 

 geologist or mining engineer. 



Now the cartographer knows that a map may be drawn in many 

 ways, or, as he would himself say, many kinds of projection are 

 available. Each one has its merits, but it is impossible to find all 

 the merits we might reasonably desire combined in one single map. 

 It is reasonable to demand that each bit of territory should look its 

 proper shape on the map; also that each should look its proper 

 relative size. Yet even these very reasonable requirements cannot 



