﻿146 
  JOURNAL 
  OF 
  THE 
  WASHINGTON 
  ACADEMY 
  OF 
  SCIENCES 
  VOL. 
  12, 
  NO. 
  6 
  

  

  or 
  short, 
  or 
  a 
  period 
  of 
  time 
  protracted 
  or 
  brief, 
  depends 
  upon 
  the 
  

   rate 
  of 
  motion 
  of 
  the 
  observer 
  with 
  respect 
  to 
  the 
  system 
  which 
  con- 
  

   tains 
  them, 
  and 
  since 
  there 
  is 
  no 
  criterion 
  of 
  absolute 
  motion, 
  one 
  

   observer's 
  results 
  are 
  as 
  good 
  as 
  those 
  of 
  any 
  other. 
  The 
  ultimate 
  

   units 
  of 
  physical 
  science 
  are 
  shown 
  to 
  be 
  purely 
  relative 
  to 
  the 
  con- 
  

   ditions 
  of 
  their 
  establishment. 
  Such 
  are 
  the 
  assumptions 
  which 
  are 
  

   necessary 
  to 
  the 
  simplest 
  and 
  apparently 
  the 
  only 
  plausible 
  solution 
  

   of 
  the 
  conflicts 
  between 
  the 
  systems 
  of 
  physical 
  data 
  which 
  have 
  

   developed 
  from 
  astronomical, 
  optical 
  and 
  electro-magnetic 
  observa- 
  

   tions. 
  In 
  this 
  situation 
  we 
  see 
  the 
  purposes 
  and 
  the 
  facts 
  of 
  physics 
  

   itself 
  driving 
  the 
  physicist 
  into 
  a 
  repudiation 
  of 
  the 
  last 
  scrap 
  of 
  em- 
  

   pirical 
  meaning 
  which 
  it 
  would 
  be 
  possible 
  otherwise 
  by 
  the 
  greatest 
  

   effort 
  of 
  imagination 
  to 
  read 
  into 
  his 
  system. 
  Thus, 
  in 
  spite 
  of 
  the 
  

   realism 
  of 
  the 
  naive 
  and 
  materialistic 
  mind, 
  does 
  psychology 
  at 
  last 
  

   fall 
  heir 
  to 
  the 
  whole 
  of 
  its 
  natural 
  estate: 
  the 
  totality 
  of 
  immediate 
  

   experience. 
  

  

  What 
  under 
  these 
  circumstances 
  may 
  we 
  consider 
  to 
  be 
  the 
  estate 
  

   of 
  physics? 
  Physical 
  formulae, 
  although 
  robbed 
  of 
  their 
  empirical 
  

   meaning, 
  nevertheless 
  purport 
  to 
  describe 
  a 
  permanent 
  external 
  

   system 
  of 
  things. 
  How 
  shall 
  we 
  conceive 
  the 
  intrinsic 
  nature 
  of 
  this 
  

   external 
  system 
  and 
  what 
  exactly 
  are 
  its 
  relations 
  with 
  the 
  system 
  

   of 
  immediate 
  experience? 
  If 
  space, 
  mass 
  and 
  time, 
  as 
  we 
  ordinarily 
  

   conceive 
  them, 
  cannot 
  be 
  supposed 
  to 
  exist 
  in 
  this 
  objective 
  physical 
  

   system, 
  it 
  is 
  still 
  possible 
  that 
  fundamental 
  dimensions 
  of 
  a 
  different 
  

   character 
  may 
  exist 
  and 
  be 
  such 
  as 
  to 
  resolve 
  the 
  conflict 
  between 
  the 
  

   results 
  of 
  separate 
  observers 
  formulated 
  in 
  ordinary 
  C. 
  G. 
  S. 
  termi- 
  

   nology. 
  Minkowski's 
  symbolic 
  scheme 
  in 
  which 
  time 
  is 
  made 
  a 
  fourth 
  

   dimension 
  — 
  coordinate 
  with 
  the 
  three 
  dimensions 
  of 
  space 
  — 
  suggests 
  

   a 
  system 
  of 
  this 
  sort 
  but 
  is 
  not 
  the 
  only 
  alternative 
  nor 
  is 
  it 
  a 
  very 
  

   intelligible 
  one. 
  

  

  This 
  is 
  the 
  mystery 
  into 
  which 
  modern 
  physics 
  has 
  led 
  us. 
  The 
  prob- 
  

   lem 
  of 
  the 
  nature 
  of 
  the 
  external 
  universe 
  which 
  physics 
  set 
  out 
  to 
  

   solve 
  has 
  virtually 
  been 
  abandoned 
  by 
  the 
  physicist, 
  for 
  his 
  present- 
  

   day 
  description 
  of 
  the 
  universe 
  is 
  couched 
  in 
  terms 
  and 
  in 
  a 
  form 
  to 
  

   which 
  we 
  can 
  assign 
  no 
  direct 
  empirical 
  meaning. 
  He 
  provides 
  us 
  

   with 
  the 
  logical 
  skeleton 
  of 
  a 
  system 
  which 
  has 
  no 
  living 
  tissue. 
  What 
  

   can 
  we 
  do 
  to 
  bring 
  this 
  skeleton 
  to 
  life? 
  In 
  this 
  situation 
  it 
  seems 
  that 
  

   physics 
  itself 
  can 
  provide 
  us 
  with 
  no 
  further 
  assistance 
  and 
  it 
  is 
  there- 
  

   fore 
  necessary 
  to 
  turn 
  back 
  to 
  the 
  sister 
  science, 
  psychology, 
  whose 
  

  

  