﻿108 
  ORGANISM 
  AND 
  MECHANISM 
  

  

  concept 
  of 
  energy 
  is 
  emphasised, 
  or 
  a 
  chemico-physical 
  de- 
  

   scription 
  which 
  is 
  ideally 
  mechanical, 
  that 
  is, 
  theoretically 
  

   reducible 
  to 
  matter-and-motion 
  description, 
  though, 
  as 
  a 
  mat- 
  

   ter 
  of 
  fact, 
  the 
  reduction 
  may 
  not 
  have 
  been 
  as 
  yet 
  effected. 
  

   A 
  mechanistic 
  description, 
  in 
  short, 
  is 
  in 
  terms 
  of 
  the 
  funda- 
  

   mental 
  concepts 
  of 
  physics 
  and 
  chemistry; 
  and 
  it 
  is 
  the 
  

   most 
  precise 
  and 
  most 
  thorough 
  kind 
  of 
  description 
  that 
  is 
  

   known. 
  

  

  Given 
  three 
  good 
  observations 
  of 
  a 
  comet, 
  an 
  astronomer 
  

   who 
  knows 
  his 
  business 
  can 
  prophesy 
  with 
  certainty 
  when, 
  

   barring 
  accidents, 
  it 
  will 
  return. 
  He 
  may 
  not 
  tell 
  us 
  what 
  

   gravitation 
  means, 
  or 
  what 
  the 
  comet 
  is 
  made 
  of, 
  or 
  how 
  

   it 
  arose, 
  or 
  what 
  it 
  portends 
  to 
  mankind, 
  but 
  of 
  the 
  com- 
  

   ing 
  and 
  going 
  he 
  gives 
  a 
  complete 
  account, 
  as 
  the 
  punctual 
  

   return 
  of 
  the 
  comet 
  afterwards 
  proves. 
  Now 
  the 
  question 
  

   which 
  interests 
  us 
  at 
  present 
  is 
  not 
  whether 
  the 
  biologist, 
  

   if 
  he 
  knew 
  his 
  business 
  as 
  well 
  as 
  the 
  astronomer, 
  could 
  

   tell 
  us 
  at 
  what 
  precise 
  date 
  next 
  spring 
  the 
  swallows 
  will 
  

   reach 
  our 
  shores, 
  but 
  rather 
  whether 
  the 
  success 
  of 
  his 
  predic- 
  

   tion 
  depends 
  on 
  the 
  reduction 
  of 
  the 
  swallows' 
  behaviour 
  

   to 
  mechanistic 
  formulation. 
  

  

  The 
  question 
  may 
  be 
  split 
  into 
  two. 
  The 
  first 
  is: 
  How 
  

   far, 
  as 
  a 
  matter 
  of 
  fact, 
  can 
  characteristically 
  vital 
  occur- 
  

   rences, 
  such 
  as 
  the 
  contraction 
  of 
  a 
  muscle, 
  be 
  described 
  in 
  

   terms 
  of 
  the 
  formula 
  which 
  serve 
  for 
  the 
  study 
  of 
  tides 
  

   and 
  eclipses, 
  the 
  moulding 
  of 
  a 
  dew-drop 
  or 
  the 
  making 
  of 
  

   a 
  star 
  ? 
  One 
  obvious 
  limit 
  is 
  that, 
  if 
  the 
  organism 
  has 
  mental- 
  

   ity 
  that 
  counts 
  in 
  its 
  agency, 
  then 
  the 
  behaviour 
  cannot 
  be 
  

   completely 
  formulated 
  in 
  mechanical 
  terms. 
  Mind 
  cannot 
  

   be 
  described 
  in 
  terms 
  of 
  matter, 
  or 
  emotion 
  in 
  terms 
  of 
  mo- 
  

   tion. 
  As 
  there 
  are 
  some 
  biologists, 
  such 
  as 
  Prof. 
  Jacques 
  

   Loeb, 
  who 
  hold 
  " 
  a 
  tropism 
  theory 
  of 
  animal 
  conduct 
  " 
  which 
  

  

  