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Show WHAT IS 1 ' RELATIVITY? Have you road the mam articles on "relativity " mid have Jj ovt J ?iven any thought to the Dew theory of space and time and gravi tation After yon have gone through half a dozen pages on Hie subject, sub-ject, you will ask for more enlightenment ami perhaps decide that the reasoning is a little bil too abstruse. The theory is as strangely new as whs gravitation in Newton's ' day, or the shape ol the earth when Columbus came bach from his voyage The man who gave to us "relativity" is Einstein of Germany ' Jusl at the opening of the world war the tbeorj was being widelj discussed. Since the armistice more information has been obtained irom tho European philosophers, until now all ihe largp colleges of I . America are deep in the stud of this subject Dr. Eddington has published a hook :n which he says: Einstein shows us thai the external world ns we have always seen it is an elaborate interweaving r that world H as it actually is ami as 11 has been com rived t.. he through our imperfeel observations and the imperfect conclusions H 1o which they have led us. The ancients, in default of any knowledge of how gravity acts in other locations than at H the earth's surface, or o the insignificant position which the earth really holds in the cosmic mechanism, or ol the true shape of the globe on which we live must have supposed "up" and "down" to he directions inherent in nature, uni- versaliy the same. Eventually', with the realisation that down was merely the direction toward the center of the body on which the observer happened to be located, the concepts "up" ami "down" lost an universal significance H which they might have heen supposed to have . the pnrt H which they play in ihe external world about us was shown H to inhere in the observer i 'her than m that world it- self. It was doubtless with some difficulty that the public H nt large, in ancient and medieval times, grew into ultimate understanding of this It is with still n on difficulty that H we shall come to the parallel but more elusive understand- H ing that the distinction alway hei -t made between time aud space, and the notion that time runs on forever in a straight line divorced from all dependence upon space are H likewise the contribution of the observer to the world of H perception; 1 hat the facts inherent in the external world fl and independent of the observer are quite different H The Aery circumstance that all this is so means that H when Einstein effects his further separation between the bb- H server's conception ami the external fact, what he finds still inherent in the outside world is something new and strange H of which we have no mental picture immediately readv, for which we have no words and veu no accurate analogies. H One thought uppermost in the mind of the student crropmg for H knowledge in the abstract philosophy of Einstein 1 thai this is the agc of the specialist ami the expert. By concentrating his though1 i along one line, the German philosopher has gone beyond the ability 1 of other men to follow even when he points the wa, |