Paper PH

Descartes’  Medita'ons  

Medita-ons  1-­‐3  

First  Philosophy  

The  Medita'ons  consists  of  medita-ons  "on   First  Philosophy".  In  the  Preface  to  the  French   edi-on  of  the  Principles  of  Philosophy  in  1647,   Descartes  explains  that  by  "First  Philosophy"  he   means  metaphysics.    

Simile  

Here  he  provides  a  simile:     •  philosophy  is  like  a  tree,  with     •  metaphysics  as  the  roots,     •  physics  as  the  trunk,  and  the     •  various  sciences  (principally  medicine,   mechanics  and  morals)  as  the  branches.  

Medita-on  1  

(1)  Decep-ve  Senses  Argument   (2)  Dream  Argument   (3)  Extreme  Dream  Argument   (4)  Possibly  Deceiving  God  Argument   (5)  Actually  Deceiving  God  Argument   (6)  Product  of  Chance  Argument    

(1)  Decep-ve  Sense  Percep-on  Argument       "the  senses  do  some-mes  deceive  us  when  it  is   a  ques-on  of  very  small  and  distant  things"     *  Sense  percep-ons  are  some-mes  decep-ve,   i.e.,  they  are  not  always  reliable.  

Dream  Argument  

(2)  Dream  Argument   "How  oWen  does  my  evening  slumber  persuade   me  of  such  ordinary  things  as  these:  that  I  am   here,  clothed  in  my  dressing  gown,  seated  next   to  the  fireplace  –  when  in  fact  I  am  lying   undressed  in  bed!...  I  see  plainly  that  there  are   no  defini-ve  signs  by  which  to  dis-nguish  being   awake  from  being  asleep"    

•  It  is  possible  that  'sense  percep-ons'  in  ideal   condi-ons  of  observa-on  may  be  decep-ve,   because  they  may  not  be  sense  percep'ons  at   all,  but  dreams.    

This  argument  is  not  so  much  an  argument  that   sense  percep-ons  are  not  reliable,  as  that  we   may  not  be  having  sense  percep'ons  when  we   think  we  are  having  them.  That  is,  Descartes  is   not  arguing  that  even  if  we  are  awake,  we  may   be  deceived.  Rather  he  is  arguing  that  we  may   not  be  awake.  

Dream  Argument  

(1)  If  I  cannot  dis-nguish  with  certainty  between   sense  percep-ons  and  dreams,  then  I  cannot   believe  as  true  anything  based  on  images,  etc.     (2)  I  cannot  dis-nguish  with  certainty  between   sense  percep-ons  and  dreams.     (3)  Thus,  I  cannot  believe  as  true  anything  based   on  images,  etc.  

(3)  Extreme  Dream  Argument     "these  general  things  -­‐-­‐  eyes,  head,  hands  and   the  like  -­‐-­‐  could  be  imaginary"  

•  The  contents  of  dreams  are  not  taken  from   reality.  Dreams  have  no  basis  in  reality   whatsoever.  That  is,  there  are  no  eyes,  or   heads,  or  hands,  or  whole  bodies  in  existence,   from  which  the  dream  is  composed.  There  are   no  buildings,  no  mountains,  etc.,  from  which   my  dreams  are  composed.  

•  Another  way  of  pu]ng  this  is  to  say  that  the   dream-­‐world  truly  is  an  inven-on.    

(1)  If  I  cannot  dis-nguish  with  certainty  between   sense  percep-ons  and  dreams,  then  I  cannot   believe  anything  as  true.     (2)  I  cannot  dis-nguish  with  certainty  between   sense  percep-ons  and  dreams.     (3)  Thus,  I  cannot  believe  anything  as  true.    

(4)  Possibly  Deceiving  God  Argument    

"there  exists  a  God  who  is  able  to  do  anything   and  by  whom  I,  such  as  I  am,  have  been  created.   How  do  I  know  that  he  did  not  bring  it  about   that  there  is...  no  extended  thing,  no  shape,  no   size,  no  place...  may  I  not...  be  deceived  every   -me  I  add  two  and  three  or  count  the  sides  of  a   square,  or  perform  an  even  simpler  opera-on,  if   that  can  be  imagined?"    

It  is  possible  that  God  has  created  me  in  such  a   way  that  even  when  I  reason  about  arithme-c   and  geometry,  etc.,  I  am  in  error.  It  is  possible   that  it  is  not  true  that  2  +  3  =  5,  or  that  a  square   has  four  sides.     (This  doubt  assumes  that  God  exists.)  

(1)  God  exists.   (2)  God  created  me.   (3)  God  may  be  a  deceiver.   (4)  Thus,  I  may  be  deceived  when  I  reason  about   mabers  of  arithme-c  and  geometry.    

(5)  Actually  Deceiving  God  Argument  

"if  it  were  repugnant  to  his  goodness  to  have   created  me  such  that  I  be  deceived  all  the  -me,   it  would  also  seem  foreign  to  that  same   goodness  to  permit  me  to  be  deceived  even   occasionally.  But  [I  am  deceived  occasionally,  so]   we  cannot  make  this  last  asser-on."  

This  is  the  argument  that  we  know  that  we  are   deceived  on  occasion,  and  we  know  that  God  is   our  creator,  so  it  seems  as  if  God  has  created  us   in  such  a  way  that  we  are  deceived.  So  God  does   indeed  deceive  us,  or  allows  us  to  be  deceived,   about  certain  mabers.  So  it  is  possible  that  I  am   deceived  in  my  reasoning  about  these  mabers.  

(1)  God  exists.   (2)  God  created  me.   (3)  I  am  deceived  about  certain  mabers.   (4)  So,  God  deceives  me,  or  allows  me  to  be  deceived,   about  certain  mabers.   (5)  So,  God  is  a  deceiver.   (6)  So,  God  may  deceive  me,  or  allow  me  to  be  deceived,   when  I  reason  about  mabers  of  arithme-c  and  geometry.     (7)  I  may  be  deceived  when  I  reason  about  mabers  of   arithme-c  and  geometry.      

(6)  Product  of  Chance  Argument      

"suppose  that  I  came  to  be  what  I  am  either  by   fate,  or  by  chance,  or  by  a  connected  chain  of   events,  or  by  some  other  way.  But  because   being  deceived  and  being  mistaken  appear  to  be   a  certain  imperfec-on,  the  less  powerful  they   take  the  author  of  my  origin  to  be,  the  more   probable  it  will  be  that  I  am  so  imperfect  that  I   am  always  deceived."  

(1)  If  I  am  the  product  of  chance,  not  design,   then  I  am  imperfect.   (2)  I  am  the  product  of  chance,  not  design.   (3)  I  am  imperfect.   (4)  If  I  am  imperfect,  then  I  may  be  deceived   when  I  reason  about  mabers  of  arithme-c  and   geometry.     (5)  I  may  be  deceived  when  I  reason  about   mabers  of  arithme-c  and  geometry.      

Summary  of  Doubts  5  and  6  

If  God  exists,  He  is  a  deceiver,  and  so  it  is   possible  that  I  am  deceived  in  reasoning  about   these  mabers  of  arithme-c  and  geometry.  And   if  God  does  not  exist,  then  I  am  merely  the   product  of  chance,  and  so  it  is  possible  that  I  am   deceived  in  reasoning  about  these  mabers  of   arithme-c  and  geometry.  Either  way,  it  is   possible  that  I  am  deceived  in  reasoning  about   these  mabers  of  arithme-c  and  geometry.    

Evil  Demon  

"Accordingly,  I  will  suppose...  an  evil  genius,   supremely  powerful  and  clever,  who  has  directed   his  en-re  effort  at  deceiving  me.  I  will  regard  the   heavens,  the  air,  the  earth,  colors,  shapes,  sounds,   and  all  external  things  as  nothing  but  the  bedeviling   hoaxes  of  my  dreams,  with  which  he  lays  snares  for   my  credulity.  I  will  regard  myself  as  not  having   hands,  or  eyes,  or  flesh,  or  blood,  or  any  senses,  but   as  nevertheless  falsely  believing  that  I  possess  all   these  things"  

Medita-on  2  

“Cogito  ergo  sum”  (Replies  to  the  Second  Set  of   Objec-ons)     “ego  sum,  ego  existo”  (Medita-ons)  

"Is  it  then  the  case  that  I  too  do  not  exist?...  there  is   some  deceiver  or  other  who  is  supremely  powerful   and  supremely  sly  and  who  is  always  deliberately   deceiving  me.  Then  too  there  is  no  doubt  that  I   exist,  if  he  is  deceiving  me.  And  let  him  do  his  best   at  decep-on,  he  will  never  bring  it  about  that  I  am   nothing  so  long  as  I  shall  think  that  I  am  something.   Thus,  aWer  everything  has  been  most  carefully   weighed,  it  must  finally  be  established  that  this   pronouncement  "I  am,  I  exist"  [ego  sum,  ego  existo]   is  necessarily  true  every  -me  I  uber  it  or  conceive  it   in  my  mind."  

Existence  Argument  

(1)  If  I  am  not  being  deceived,  then  I  exist.   (2)  If  I  am  being  deceived,  then  I  exist.   (3)  So,  if  I  am  either  being  deceived  or  not  being   deceived,  then  I  exist.   (4)  I  am  either  being  deceived  or  not  being   deceived.   (5)  Therefore,  I  exist.    

Argument  for  premise  2  

(1)  If  I  am  being  deceived,  then  I  am  thinking.   (2)  If  I  am  thinking,  then  I  exist.     (3)  Therefore,  if  I  am  being  deceived,  then  I   exist.      

Cogito  ergo  sum  

(s-ll  from  premise  2)   (1)  If  I  am  thinking,  then  I  exist.   (2)  I  am  thinking.   (3)  Therefore,  I  exist.     Is  Descartes  en-tled  to  premise  2  directly   above?  How  does  he  know  that  there  is  an  "I"   that  is  having  these  thoughts?      

If  the  claim  is  restricted  to  the  claim  that  "There  is  a   thought",  or  "A  thought  exists",  or  "A  thought  is   occurring",  the  argument  would  be  as  follows:           (1)  If  a  thought  exists,  then  I  exist.   (2)  A  thought  exists.   (3)  Therefore,  I  exist.    

(1)  If  a  thought  exists,  then  a  mind  exists.   (2)  A  thought  exists.   (3)  Therefore,  a  mind  exists.       But  Descartes  wants  to  argue  that  his  mind   exists.  

(1)  A  thought  exists.   (2)  If  a  thought  exists,  then  a  mind  exists.   (3)  The  thought  that  exists  is  a  thought  of  my   mind.   (4)  Therefore,  my  mind  exists.     (3)  is  ques-on-­‐begging  

If  Descartes  already  knows  that  the  thought  that   exists  is  his  own  thought,  then  he  already  knows   that  it  is  a  thought  of  his  own  mind,  and  hence,   he  already  knows  that  his  own  mind  exists.  

The  argument  really  seems  to  be:    

My  mind  exists  (or  I  exist)  because  my  thoughts   exist.   •  What  Descartes  needs  to  prove  is  that  the   exis-ng  thoughts  are  my  thoughts.  He  cannot   prove  that  "my  thoughts  exist"  is  true.  If  he   simply  assumes  that  "my  thoughts  exist"  is   true,  then  he  hasn't  proven  anything.  He   hasn't  proven  that  "I  exist"  is  true.  

Medita-on  3   Clear  and  Dis-nct  Percep-ons  

  One  conclusion  of  Medita-on  Two  is  that  "I  exist"  is   "necessarily  true  every  -me  I  uber  it  or  conceive  it   in  my  mind”.  Another  conclusion,  apparently,  is   that  I  am,  or  am  at  least,  "a  thing  that  thinks,  that  is   to  say,  a  thing  that  doubts,  affirms,  denies,   understands  a  few  things,  is  ignorant  of  many   things,  wills,  refrains  from  willing,  and  also  imagines   and  senses.”  That  is,  "I  am  certain  that  I  am  a   thinking  thing."    

•  Does  he  now  have  a  principle  by  which  he   may  arrive  at  truths?  

•  He  argues  that  he  "clearly  and  dis-nctly   perceives"  that  he  exists,  and  that  he  is  a   thinking  thing.  

Rule  of  Clarity  and  Dis-nctness  

"But  do  I  not  therefore  also  know  what  is  required   for  me  to  be  certain  of  anything?  Surely  in  this  first   instance  of  knowledge,  there  is  nothing  but  a   certain  clear  and  dis-nct  percep-on  of  what  I   affirm.  Yet  this  would  hardly  be  enough  to  render   me  certain  of  the  truth  of  a  thing,  if  it  could  ever   happen  that  something  that  I  perceived  so  clearly   and  dis-nctly  were  false.  And  thus  I  now  seem  to   be  able  to  posit  as  a  general  rule  that  everything  I   very  clearly  and  dis-nctly  perceive  is  true."    

Rule  of  Clarity  and  Dis-nctness  

Whatever  idea  or  judgment  I  clearly  (i.e.  "when   it  is  present  and  accessible  to  the  aben-ve   mind")  and  dis-nctly  (i.e.  "is  so  sharply   separated  from  all  other  percep-ons  that  it   contains  within  itself  only  what  is  clear")   perceives,  is  true.  That  is:       If  I  clearly  and  dis-nctly  perceive  that  p,  then  p   is  true.    

Argument  for  the  Existence  of  God  

•  The  Idea  of  God  Cannot  Be  Merely  Subjec-ve   •  Descartes'  first  argument  for  the  existence  of   God  is  based  on  two  principles.  

1.  Principle  of  Sufficient  Reason  (SR)  -­‐-­‐  the  thesis   that  everything  has  a  cause.  

2.  Principle  of  Adequate  Reality  (AR)  -­‐-­‐  the  thesis   that  there  must  be  at  least  as  much  reality  in   the  cause  as  the  effect  (e.g.,  heat  is  induced  by   something  hot,  etc.).  Note:  Descartes  believes   that  AR  follows  from  SR.  

(1)  I  have  an  idea  of  God.  (given)   (2)  This  idea  must  have  a  cause.  (SR)   (3)  There  cannot  be  less  reality  in  the  cause  than   in  the  effect.  (AR)    

(4)  If  the  cause  of  my  idea  of  God  were  anything   but  God,  there  could  be  less  reality  in  the  cause   than  in  the  effect  (because  the  degree  of  reality  of   an  idea  determines  what  it  is  an  idea  of).     [Descartes  appeals  to  the  fact  that  infinity  and   perfec'on  generally  cannot  be  built  up  out  of  finite   imperfect  experiences.]     (5)  Therefore,  God  exists.  

Wednesday:  Medita-ons  3-­‐6     Friday:  Agora  Day