﻿THE 
  UNFATHOMED 
  UNIVERSE 
  23 
  

  

  than 
  approximate, 
  extension 
  or 
  intensification 
  of 
  inquiry 
  

   may 
  show 
  that 
  it 
  does 
  not 
  apply 
  beyond 
  certain 
  limits. 
  Thus 
  

   the 
  law 
  of 
  gravitation, 
  which 
  must 
  be 
  very 
  near 
  to 
  perfect 
  

   accuracy 
  when 
  applied 
  to 
  planetary 
  distances, 
  may 
  not 
  hold 
  

   either 
  for 
  very 
  minute 
  molecular 
  distances 
  or 
  for 
  immense 
  

   stellar 
  distances. 
  

  

  (3) 
  Even 
  generalisations 
  that 
  work 
  well 
  and 
  must 
  bear 
  

   a 
  close 
  correspondence 
  to 
  reality, 
  since 
  they 
  afford 
  a 
  basis 
  

   for 
  effective 
  prophecy, 
  may 
  require 
  some 
  modification, 
  in 
  

   their 
  setting 
  at 
  least, 
  in 
  the 
  light 
  of 
  some 
  new 
  fact 
  or 
  idea, 
  

   of 
  great 
  magnitude. 
  Thus 
  Prof. 
  Frederick 
  Soddy 
  writes 
  : 
  

   " 
  It 
  sounds 
  incredible, 
  but 
  nevertheless 
  it 
  is 
  true, 
  that 
  

   science 
  up 
  to 
  the 
  close 
  of 
  the 
  nineteenth 
  century 
  had 
  no 
  sus- 
  

   picion 
  even 
  of 
  the 
  existence 
  of 
  the 
  original 
  sources 
  of 
  natural 
  

   energy. 
  . 
  . 
  . 
  The 
  vista 
  which 
  has 
  been 
  opened 
  up 
  by 
  

   these 
  new 
  discoveries 
  [of 
  the 
  radio-active 
  properties 
  of 
  

   some 
  substances] 
  is 
  without 
  parallel 
  in 
  the 
  whole 
  his- 
  

   tory 
  of 
  science 
  ' 
  (Harper's 
  Magazine, 
  December, 
  1909, 
  p. 
  

   53). 
  

  

  (4) 
  We 
  cannot 
  pass 
  over 
  the 
  caution 
  suggested 
  by 
  the 
  

   Michelson-Morley 
  experiment, 
  which 
  showed 
  that 
  scientific 
  

   observations 
  cannot 
  transcend 
  the 
  system 
  in 
  which 
  they 
  are 
  

  

  - 
  immersed. 
  In 
  Prof. 
  Wildon 
  Carr's 
  words, 
  " 
  It 
  showed 
  us 
  

   that 
  observers 
  within 
  a 
  system 
  of 
  reference, 
  in 
  uniform 
  move- 
  

   ment 
  of 
  translation 
  relatively 
  to 
  other 
  systems, 
  have 
  no 
  

   absolute 
  standard 
  by 
  which 
  they 
  can 
  determine 
  their 
  move- 
  

   ment. 
  There 
  is 
  no 
  absolute 
  ether, 
  no 
  absolute 
  space, 
  and 
  no 
  

   absolute 
  time, 
  by 
  reference 
  to 
  which 
  we 
  can 
  determine 
  our 
  

   movements" 
  (1918, 
  p. 
  21). 
  And 
  Prof. 
  Max 
  Planck 
  

   writes 
  of 
  this 
  new 
  idea 
  of 
  the 
  relativity 
  of 
  time: 
  With 
  

   the 
  revolution 
  which 
  it 
  brings 
  about 
  in 
  our 
  conception 
  of 
  

   the 
  physical 
  universe, 
  no 
  other 
  is 
  comparable, 
  in 
  range 
  

  

  