﻿396 
  PROFESSOR 
  ALISON'S 
  DEFENCE 
  

  

  stead 
  of 
  straining 
  the 
  principles 
  of 
  other 
  sciences 
  formerly 
  ascertained, 
  to 
  make 
  

   them 
  include 
  phenomena 
  admitted 
  to 
  be 
  distinct 
  from 
  any 
  of 
  those 
  to 
  which 
  they 
  

   have 
  formerly 
  been 
  applied, 
  — 
  it 
  becomes 
  our 
  duty 
  to 
  attempt 
  the 
  investigation 
  

   and 
  determination 
  of 
  laws 
  peculiar 
  to 
  this 
  department 
  of 
  nature. 
  If 
  these 
  laws 
  

   shall 
  ultimately 
  resolve 
  themselves 
  into 
  any 
  previously 
  known 
  and 
  more 
  general 
  

   laws 
  of 
  nature, 
  science 
  will 
  be 
  simplified, 
  and 
  a 
  great 
  advance 
  made 
  ; 
  but 
  it 
  is 
  

   assuredly 
  mistaking 
  the 
  right 
  order 
  of 
  inquiry 
  to 
  assert 
  that, 
  because 
  such 
  simpli- 
  

   fication 
  may 
  ultimately 
  be 
  effected, 
  therefore 
  we 
  are 
  now 
  to 
  decline 
  giving 
  these 
  

   phenomena 
  an 
  appropriate 
  name, 
  and 
  endeavouring 
  to 
  reduce 
  them 
  to 
  general 
  

   laws 
  by 
  an 
  induction 
  limited 
  to 
  this 
  department 
  of 
  nature 
  itself. 
  

  

  This 
  is 
  the 
  principle 
  which 
  has 
  been 
  successfully 
  followed 
  in 
  other 
  departments 
  

   of 
  science. 
  Speculations 
  have 
  been 
  hazarded 
  as 
  to 
  the 
  cause 
  of 
  the 
  principle 
  of 
  

   Gravitation 
  itself. 
  I 
  recollect 
  that 
  the 
  late 
  Mr 
  Playfair 
  used 
  to 
  say 
  a 
  few 
  words 
  

   in 
  favour 
  of 
  one 
  of 
  these, 
  the 
  theory 
  of 
  Ultra 
  Mundane 
  Particles 
  continually 
  

   moving 
  in 
  all 
  directions 
  through 
  all 
  space, 
  although 
  not 
  making 
  themselves 
  

   known 
  to 
  the 
  human 
  senses 
  ; 
  which, 
  if 
  admitted, 
  would 
  resolve 
  the 
  principle 
  of 
  

   gravitation 
  into 
  that 
  of 
  motion 
  communicated 
  by 
  impulse. 
  But 
  no 
  one 
  will 
  main- 
  

   tain 
  that 
  it 
  was 
  incumbent 
  on 
  Newton 
  to 
  prove, 
  that 
  this 
  theory 
  would 
  not 
  ex- 
  

   plain 
  the 
  phenomena, 
  before 
  asserting 
  the 
  principle 
  of 
  gravitation, 
  and 
  determin- 
  

   ing, 
  by 
  observation 
  and 
  experiment, 
  the 
  laws 
  according 
  to 
  which 
  that 
  principle 
  

   acts, 
  or 
  by 
  which 
  the 
  phenomena 
  coming 
  under 
  that 
  head 
  are 
  regulated. 
  It 
  is, 
  

   indeed, 
  observed 
  in 
  many 
  departments 
  of 
  science, 
  that 
  one 
  great 
  difficulty 
  in 
  the 
  

   early 
  inquiries 
  is, 
  to 
  keep 
  the 
  inquirers 
  from 
  deviating 
  into 
  lines 
  of 
  research 
  which 
  

   they 
  may 
  think 
  analogous 
  to 
  their 
  own, 
  and 
  applying 
  prematurely 
  principles 
  

   which 
  have 
  been 
  established 
  by 
  an 
  induction 
  of 
  very 
  different 
  facts. 
  This 
  is 
  the 
  

   error 
  which 
  Dr 
  Reid 
  made 
  an 
  object 
  of 
  special 
  remark 
  when 
  speaking 
  of 
  the 
  

   " 
  enumeration 
  of 
  the 
  original 
  powers 
  and 
  laws 
  of 
  our 
  mental 
  constitution." 
  

   " 
  Success 
  in 
  an 
  inquiry 
  of 
  this 
  kind 
  it 
  is 
  not 
  in 
  human 
  nature 
  to 
  command 
  ; 
  but 
  

   perhaps 
  it 
  is 
  possible, 
  by 
  caution 
  and 
  humility, 
  to 
  avoid 
  error 
  or 
  delusion. 
  The 
  

   labyrinth 
  may 
  be 
  too 
  intricate 
  to 
  be 
  traced 
  through 
  all 
  its 
  windings 
  ; 
  but 
  if 
  we 
  

   stop 
  when 
  w^e 
  can 
  trace 
  it 
  no 
  farther, 
  and 
  secure 
  the 
  ground 
  we 
  have 
  gained, 
  there 
  

   is 
  no 
  harm 
  done 
  ;a 
  quicker 
  eye 
  may 
  in 
  time 
  trace 
  it 
  further." 
  — 
  {Hamilton 
  's 
  edition 
  

   of 
  Reid, 
  p. 
  40.) 
  In 
  physiology 
  itself, 
  it 
  is 
  a 
  similarly 
  just 
  and 
  comprehensive 
  obser- 
  

   vation 
  of 
  Mr 
  Lawrence, 
  " 
  that 
  although 
  organised 
  bodies 
  are 
  subjected 
  in 
  many 
  

   respects 
  to 
  plrysical 
  laws, 
  yet, 
  as 
  regards 
  their 
  own 
  peculiar 
  phenomena, 
  the 
  refer- 
  

   ence 
  to 
  gravity, 
  to 
  attraction, 
  to 
  chemical 
  affinity, 
  to 
  electricity 
  or 
  galvanism, 
  

   can 
  only 
  serve 
  to 
  perpetuate 
  false 
  notions 
  in 
  physiology, 
  and 
  to 
  draw 
  us 
  away 
  

   from 
  the 
  proper 
  point 
  of 
  view 
  in 
  which 
  the 
  nature 
  of 
  living 
  phenomena, 
  and 
  the 
  

   properties 
  of 
  living 
  beings, 
  ought 
  to 
  be 
  considered." 
  — 
  {Two 
  Introductory 
  Lectures, 
  

   p. 
  161.) 
  It 
  was 
  the 
  same 
  idea, 
  not, 
  perhaps, 
  so 
  accurately 
  conceived, 
  but 
  more 
  

   graphically 
  announced, 
  which 
  prompted 
  Dr 
  William 
  Hunter's 
  remark, 
  in 
  com- 
  

  

  