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Medieval  Theories  of  Causal  Powers  Thomas  Aquinas,  Henry  of  Ghent,  Duns  Scotus,  and  William  Ockham  

   

JT  Paasch      ABSTRACT:   Powers   and   dispositions   seem   to   be   perfectly   real   features   of   things.   For  instance,  wine  glasses  are  fragile,  sugar  is  soluble,  dry  twigs  are  combustible,  and  so  on.  But   what   exactly   are   powers   and   dispositions   like   “fragility”   or   “solubility”?   Are   they  “things”?  Do   they  have  parts  and  take  up  space?  Where  are   they   located?  And  how  are  they   connected   to   the   other   features   of   their   possessors?   In   this   paper,   I   examine   the  scholastic  debate  about  this,  and  I  find  three  separate  theories.  First,  Aquinas  proposes  a  “two-­‐category”  theory:  there  are  categorical  entities,  and  there  are  dispositional  entities  in   the   world.   Second,   Henry   of   Ghent   proposes   a   “two-­‐aspects”   theory:   there   are   just  categorical   entities   in   the   world,   but   they   can   have   both   a   categorical   aspect   and   a  dispositional  aspect.  Third,  Duns  Scotus  and  William  Ockham  propose  a  “one-­‐category”  theory:  there  are  just  categorical  entities  and  no  dispositional  entities  in  the  world,  and  “powers”  or  “dispositions”  are  nothing  more  than  the  categorical  parts  and  materials  of  things  that  cause  the  various  effects  we  see  around  us.            

The   subject   of   this   paper   is   powers   and   dispositions.     Powers   and  dispositions  are  roughly  just  the  capabilities  and  capacities  that  things  have  to   act   in   certain   ways.   For   instance,   I   am   capable   of   doing   a   number   of  different  things.  I  can  raise  my  arm,  I  can  stand  up  and  sit  down,  I  can  think  through  complex  issues,  I  can  make  choices,  and  so  on.  These,  we  might  say,  are  all  things  that  are  within  my  power;  they  are  all  things  I  have  the  power  to  do.    

Furthermore,  powers  or  dispositions  are  not  just  for  doing   things.  Most  objects   can   have   various   things   done   to   them   as   well.   For   instance,   wine  glasses  can  be  shattered,  sugar  can  be  dissolved,  my  arm  can  be  raised  (by  me,  or  by  a  pulley  system),  and  so  on.  The  capacities  to  undergo  such  things  are,   in   one   way   or   another,   capacities   to   behave   in   certain   ways,   so   they  count  as  powers  or  dispositions  too.1                                                                                                                  1  Some  might  want  to  say  that  the  term  “powers”  most  naturally  refers  to  abilities  to  do  things,  whereas  the  term  “dispositions”  most  naturally  refers  to  capacities  to  undergo  things,  but  I  will  not  draw  any  sharp  distinction  between  “powers”  and  “dispositions”  here.  Instead,  I  will  use  the  terms  interchangeably.      

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But  what  exactly  are  powers  or  dispositions?  Are  they  discrete  physical  items,  for  instance?  Supposing  we  had  the  right  laboratory  equipment,  could  we  (at   least   in  principle)  cut  a  power  off   its  possessor  and  study  it  under  a  microscope?   Do   powers   take   up   space,   or   have   parts?   On   the   other   hand,  maybe   these   are   the   wrong   sorts   of   questions,   for  maybe   powers   are   not  physical  items  at  all.  Well,  if  that  is  so,  then  what  are  they,  precisely?    

Analytic   philosophers   have   spent   a   good   deal   of   time   discussing   these  matters,   and   there   is   a   substantial   body   of   literature   on   the   subject.   But  analytic  philosophers  are  not   the  only  ones  who  debated   these   issues.  The  scholastics   did   too.   Anyone   who   has   spent   even   a   small   amount   of   time  reading   scholastic   philosophy   will   recognize   a   word   that   crops   up   quite  often  in  the  texts:  namely  potentia,  the  scholastic  term  for  “power.”  It  shows  up   in   scholastic   discussions   about   change,   material   substances,   mind   and  cognition,  and  even  theology.    

Yet   despite   this   pervasiveness,   there  was  no   “standard”  medieval   view  about  powers.  On  the  contrary,  there  were  a  number  of  competing  theories  about  the  nature  of  powers,  much  as  there  is  today.  So,  what  were  some  of  those  theories?  That  is  the  question  I  want  to  address  in  this  paper.  

As  we  shall  see,  there  were  (at  least)  three  basic  positions  the  scholastics  could  take.  One  was  reductive:  there  is  no  need  to  postulate  special  entities  called  “powers,”  for  powers  can  be  reduced  to  or  explained  in  terms  of  other,  more   readily   understandable   things.   Another   option   was   non-­‐reductive:  powers  cannot  be  reduced   to  or  explained   in   terms  of  other   things;  on   the  contrary,  they  are  unique  sorts  of  entities  all  to  their  own.  And  there  was  a  third  option  that  tried  to  take  the  middle  road.  

   

Preliminary  Questions:  Powers  and  Their  Exercise    

One  of  the  more  distinctive  marks  of  powers  is  that  they  only  get  exercised  sometimes.  I  may  have  the  ability  to  raise  my  arm,  but  I  am  not  always  doing  so.  I  do  not  walk  around  with  my  arm  in  the  air,  nor  do  I  sleep  with  my  arm  in  the  air,  for  instance.  I  only  raise  my  arm  sometimes.  To  say  that  I  have  the  power   to   raise  my   arm   does   not   describe   some   static   state   of  me   and   the  position  of  my  arm.  Rather,  it  seems  to  say  something  about  the  possibility  of  me  raising  my  arm.    

Of   course,   it   is   possible   that   my   arm   be   raised   independently   of   my  power   to   raise   my   own   arm.   You   could   lift   my   arm   up,   my   arm   could   be  raised  by  a  pulley  system,  and  so  on.  But  that  would  not  be  the  direct  result  of  my   power   to   raise  my   arm.   It  would   be   the   result   of   your   power   to   lift  things  (like  my  arm),  the  pulley  system’s  power  to  hoist  things  up,  etc.    

Still,   you   are   not   constantly   lifting   things   (like   my   arm),   and   pulley  systems  are  not  constantly  hoisting  things  up  either.  Again  then,  to  say  that  you   have   the   power   to   lift   things   seems   to   say   something   about   the  

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possibility   of   you   lifting   things,   and   the   same   goes   for   a   pulley   system’s  power  to  hoist  things  up.  To  say  that  something  has  a  power  means  it  has  a  capability   that  could   get  exercised  —  maybe  not  now,  but  perhaps  at   some  other  time.    

This  makes  powers   somewhat  perplexing.   For  one   thing,   if   powers   are  only  exercised  sometimes,  then  what  explains  how  and  when  that  happens?  Why  does  any  given  power  get  exercised  at  this  time  rather  than  that  time?  And   how   does   it   get   exercised   anyway?   What,   so   to   speak,   “draws”   that  activity  out  of  it?2    

For  some  powers,  the  answer  seems  to  be  our  own  will  power,  for  some  powers   only   get   exercised  when  we   choose   to   exercise   them.  My   ability   to  raise  my  arm,  stand  up  or  sit  down,  and  so  on  would  all  be  powers  that  we  might  class  as   “voluntary”  powers.  But  not  all  powers  and  dispositions  are  voluntary.   There   are   plenty   of   other   powers   that   seem   to   get   exercised  involuntarily.  Much  of  the  behavior  that  we  observe  between,  say,  particles  or   cells  might   be   chalked   up   as   “involuntary”   powers   and   dispositions.   So  what  explains  when  and  why  they  get  exercised?    

One  relevant  factor  seems  to  be  the  circumstances  that  are  present  when  such  powers  do  get  exercised,  for  many  such  powers  seem  to  get  exercised  only  in  certain  circumstances.  For  instance,  wine  glasses  tend  to  shatter  not  at  random,  but  rather  when  you  drop  them.  So,  we  might  think,  part  of  what  explains  how  and  why  powers  get  exercised  is  the  presence  of  the  right  set  of   circumstances.  And  we  might  even   try   to  define  powers  by  appealing   to  those  circumstances:  to  say  that  something  has  a  power  or  disposition  for  X  means  that  X  will  occur  when  it  is  in  circumstances  Y.3    

However,   it   is   notoriously   difficult   to   identify   the   right   set   of  circumstances   in   a   precise   way.   One   problem   is   that   there   are   often   too  many   alternative   sets   of   relevant   circumstances.   Wine   glasses   tend   to  shatter   when   I   drop   them,   but   they   also   tend   to   shatter   when   I   swing  baseball  bats  at  them,  when  I  drive  over  them  with  big  trucks,  and  so  on.  The  full  list  of  circumstances  for  shattering  wine  glasses  is  thus  a  very  long  one:  wine  glasses  shatter  if  they  are  dropped,  or  if  they  are  struck  by  fast  moving  baseball  bats,  and  so  on  and  so  forth.    

In  addition,  there  are  also  circumstances  that  block  powers.  For  instance,  wine   glasses   tend   to   shatter   when   I   drop   them,   but   not   if   the   floors   are  covered  with  pillows,  if  I  am  in  space  where  there  is  no  gravity,  and  so  forth.  The   list   of   relevant   circumstances   now   becomes   even   longer   and   more                                                                                                                  2  And  if  there  is  something,  call  it  X,  that  “draws”  that  activity  out,  then  wouldn’t  we  have  to  say  X  has  a  special  power  all  its  own  —  namely,  the  power  to  excite  other  powers  into  action?  But  then  what  would  draw  X’s  power  into  action?  Something  else?  We  could  go  on  ad  infinitum  here.  3  And  we  might  be  tempted  to  think  that,  if  properly  modified,  this  could  apply  to  voluntary  powers  too,  for  surely  even  voluntary  powers  require  amenable  circumstances  before  they  can  be  exercised.  After  all,  no  matter  how  badly  I  might  want  to  raise  my  arm,  I  could  not  do  so  if  it  were  tied  down.    

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complicated:  wine   glasses   shatter   if   they   are   dropped   (but   not   if   they   are  dropped   on   pillows,   if   there   is   no   gravity,   etc.),   and   so   on   and   so   forth.   A  complete   and   precise   list   of   circumstances   just   seems   impossible   to  formulate.    

Another   perplexing   factor   is   this:   if   powers   are   only   exercised  sometimes,  what  about  the  times  when  they  are  not  being  exercised?  What  is  their  status  then?  Are  they  even  there?  If  so,  where,  exactly?  Consider  my  ability  to  raise  my  arm.  I  am  not  at  this  moment  raising  my  arm,  so  that  is  a  power  I  am  not  currently  exercising.  But  where  then  is  this  power  of  mine?  Is  it  in  my  arm?  Somewhere  else?  And  what  kind  of  thing  is  it,  anyway?    

Moreover,  what   if   I  never   raised  my  arm?  Suppose   I   live  my  entire   life  without  ever  raising  my  arm  —  perhaps  it  just  never  occurs  to  me.  Would  it  make   sense   to   say   I   have   the  power   to   raise  my  arm,   even   though   I   never  exercise  that  power?  Alternatively,  suppose  I  was  born  into  captivity  and  my  arm  is  bound  to  my  side  so  that  I  cannot  raise  it,  even  if  I  want  to.  Would  I  have   the   power   to   raise   my   arm   then?   What   exactly   is   the   connection  between  a  power  and  its  exercise?  

There   does   seem   to   be   a   strong   conceptual   link   here,   for   we   often  conceptualize  powers  in  terms  of  their  exercise.  After  all,  we  do  not  say  that  Jane  has  power  without  specifying  (or  at   least   implying)  what   Jane  has   the  power   for.  And   indeed,   just   try   to   imagine  a  power   that   is  not  a  power   for  something  or  other.  It  seems  impossible  (or  at  least  I  can’t  do  it).  Whenever  we  think  of  a  power,  we  also  seem  to  think  (however  vaguely)  of  its  exercise  as  well,  and  that  suggests  that  the  one  is  somehow  intimately  connected  to  the  other.    

Further,  powers  seem  to  be  defined  by  their  exercise.  For  what  would  a  power   be   if   not   a   power   for   something   X   or   Y?   How   could   we   define  my  power  to  raise  my  arm  without  saying  it  is  for  raising  my  arm?  After  all,  if  it  weren’t  for  raising  my  arm,  it  would  be  a  power  for  something  else  (and  if  it  weren’t   for   any   activity   whatsoever,   it   wouldn’t   be   a   power   in   the   first  place).   Accordingly,   we   often   differentiate   and   categorize   powers   by   their  exercise  too.  What  is  the  difference  between  a  power  for  X  and  a  power  for  Y?  Well,  the  one  is  a  power  for  X  and  the  other  is  a  power  for  Y.  So,  it  seems,  there  is  a  very  strong  conceptual  link  between  powers  and  their  exercise.  

But   that   is   just   a   conceptual   link   —  something   that   happens   in   our  minds.  Does  it  apply  outside  our  minds  too?  Do  powers  really  have  such  an  intimate  connection  with  their  exercise?  Consider  a  power  that  is  not  being  exercised:   my   power   to   raise   my   arm,   for   instance.   How   could   that   be  connected   to   the   activity   of   raising  my   arm  when   there   is   no   arm   raising  going   on?   Surely   a   connection   with   a   non-­‐existent   activity   is   no   real  connection   at   all.   Is   the   connection   thus   supposed   to   be  with   some   future  arm   raising,   or   perhaps   with   someone   else   raising   their   arm   in   another  world?    

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Perhaps  the  connection  isn’t  one  between  particular  powers  and  events,  but   rather   one   between   types  of   powers   and   events,  where   such-­‐and-­‐such  types  of  powers  are  connected  with  such-­‐and-­‐such  types  of  events.  But  then  what  are  types?  Are  they  just  groupings  we  make  in  our  minds,  or  are  they  real   universals?   (One’s   theory   of   universals   does   not   have   to   make   a  difference  here,  but  it  certainly  could.4)  

   

More  Preliminary  Questions:  Powers  and  Their  Bases    

Another  important  question  has  to  do  with  why  things  have  the  powers  that  they  have.  Why  do   I  have  certain  kinds  of   capacities,  whereas  a  wine  glass  has   a   fairly   different   set   of   capacities?   Is   there   any   sort   of   reason   or  explanation   for   the   fact   that   certain   kinds   of   things   have   certain   kinds   of  powers  but  not  others?    

One  possibility  is  to  say  that  a  thing’s  powers  are  based  on  the  parts  and  materials  it  is  made  from.  For  instance,  the  fact  that  a  wine  glass  can  shatter  is  based  on  the  fact  that  it  is  made  from  glass.  The  glass  it  is  made  from  is,  in  a  certain  sense,   the  basis  or  source  of   its   fragility.  After  all,   if   it  were  made  from  steel,  it  would  not  be  so  fragile.    

This  also  seems   to  apply  more  generally:  powers  can  be  based  not   just  on   the   physical   parts   and   materials   a   thing   is   made   from,   but   on   certain  other  kinds  of   constituents  as  well.  A   favorite  example  of   the  scholastics   is  heat,   for   heat   not   only  makes   things   hot,   it   gives   them   the   ability   to   heat  other  things  too.  If  you  add  enough  heat  to  a  branding  iron,  a  pot  of  water,  or  any  other  heatable  thing,  it  will  then  be  able  to  burn  and  scald  other  things  as  well.    

Nevertheless,   to   say   that   a   thing’s   powers   are   based   on   its   parts   and  constituents   raises  more  questions   than   it   perhaps   answers.   For   if   powers  are   always   based   on   certain   parts,  materials,   and   other   constituents,   then  what   exactly   is   the   difference   between   powers   and   their   bases?   If   certain  kinds  of  powers  always  come  along  with  certain  kinds  of  parts  or  materials,  then  what   is   the   difference   between   having   that   particular   kind   of   power  and  having  that  particular  kind  of  part  or  constituent?  Why  not  assume  that  powers  just  are  those  parts  or  constituents?    

One   might   respond   that,   however   tempting   it   may   be   to   think   that  powers   just   are   their   bases,   this   cannot   be   so,   for   if   any   two   things   are  identical,  anything  true  of  the  one  must  also  be  true  of  the  other,  and  that  is  not   the  case   for  powers  and  their  bases.  Wine  glasses  only  shatter  some  of  the  time  (like  when  I  drop  them),  but  they  are  not  made  of  glass  only  some                                                                                                                  4  One  very  straightforward  way  to  make  sense  of  the  connection  between  powers  and  their  exercise  would  be  to  claim  that  the  connection  holds  between  universals.  Unfortunately,  this  strategy  is  not  available  to  most  scholastics,  because  most  do  not  believe  in  extramental  universals  (except,  perhaps,  in  the  Godhead).  Most  scholastics  are  more  like  trope  theorists.  

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of  the  time.  Rather,  they  are  made  of  glass  for  the  duration  of  their  life  spans.  Additionally,  there  are  other  things  that  are  fragile  but  not  made  of  glass  (a  stack  of  cards,  a  spider  web,  etc.).  So,  one  might  think,  surely  powers  cannot  be   the   same   as   the   parts   and   materials   they   are   based   on.   Glass   may   be  fragile,  but  fragility  is  not  glass.    

However,  if  powers  are  something  over  and  above  their  bases,  then  that  leaves   us   with   the   original   question:   what   exactly   are   they?   What   is   the  “fragility”   of   a   wine   glass,   if   not   the   glass   itself?   One   of   the   advantages   of  pointing   to   the   parts   and   materials   that   things   are   made   from   is   that   we  understand  parts  and  materials  better  than  powers  (or  at  least  we  think  we  do).   Parts   and   materials   have   dimensions,   take   up   space,   and   often   have  mass.   Powers,   on   the   other   hand,   are   much   more   mysterious,   especially  when  they  are  not  being  exercised.  We  can  point  to  a  piece  of  glass,  but  can  we  point  to  its  “fragility”?  Some  philosophers  have  even  used  this  insight  to  draw  a  distinction:  powers  and  dispositions  are  of  course  “dispositional”  in  nature,  but  the  parts  and  materials  things  are  made  from  are  not,  so  they  are  “categorical”  in  nature.  

On   the  other  hand,   is   it   really   true   that  bases  are  as  un-­‐power-­‐like  as   I  am   making   it   seem?   Are   categorical   parts   and   materials   really   so   non-­‐dispositional  in  nature?  Consider  a  wine  glass’s  fragility  again.  That  fragility  is  allegedly  based  on  the  glass  it  is  made  from,  but  what  is  it  about  glass  that  makes   it  a  suitable  “basis”   for   fragility?  Well,   its  molecular  structure  seems  like   a   good   candidate:   glass   has   an   unstable  molecular   structure,   and   that  explains  why  glass  is  fragile.  But  what  does  it  mean  to  be  “unstable”?  Isn’t  it  just  a   tendency  or  capacity   to  come  apart  under  certain  conditions?  Surely  that  is  just  as  much  a  disposition  as  fragility  is.  And  we  could  say  something  similar  about  mass,   the  spin  of  particles,  electrical  charge,  and  so  on:   these  basic  physical  properties  seem  to  be  dispositional  in  nature  too.    

If   that   is   so,   then   is   there   really   such   a   strong   distinction   between  powers  and   their  bases,  between   “categorical”   and   “dispositional”   entities?  Maybe   powers   and   their   bases   are   one   and   the   same   thing   after   all.   Or  maybe  the  parts  and  materials  that  things  are  made  from  can  have  aspects  of  both:  maybe  they  can  have  a  categorical  aspect,  and  a  dispositional  aspect.  

   

The  Context  of  the  Scholastic  Discussion    

When   writing   about   “medieval   theories   of   X,”   one   of   the   first   tasks   is   to  figure  out  where  it  is  in  their  writings  that  the  scholastics  talk  about  X.  This  is  not  entirely  straightforward,  for  as  is  well  known,  the  scholastics  worked  with   a   debate-­‐style   format.   University   professors   typically   began   their  lectures   with   a   yes/no   question,   such   as   “is   it   permissible   to   lie?”   They  would  then  offer  a  series  of  arguments  for  and  against,  and  then  they  would  

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extrapolate   their  own  answer   to   the  question,  which   they  of   course  would  back  up  with  more  arguments  to  boot.    

Many   of   these   yes/no   questions,   not   to   mention   the   arguments   and  solutions  that  were  offered  for  them,  became  canonized  to  the  point  that,  if  you  were  a  university  professor  in  the  13th  or  14th  century,  you  would  have  been   expected   to   discuss   them,   both   in   your   lectures   and   your   writings.  Everything  became  so  structured  around  these  canonized  yes/no  questions  that   if   you   wanted   to   discuss   some   particular   philosophical   topic   that  interested  you,  you  would  have  had  to  fit   it   in  under  one  of  the  established  questions.    

Part   of  what   this  means   is   that   a   host   of   philosophical   discussions   got  filed   under   question   headings   that   may   not   seem   entirely   relevant   to   the  modern   researcher.   Worse,   many   of   these   discussions   ended   up   getting  couched   in   the   question’s   terminology.   So,   although   some   particular  discussion   may   really   have   been   about   a   general   philosophical   topic   X,   it  might   very   well   have   been   phrased   in   terms   of   Y,   because   the   question  heading   asked   about   Y.   And   again,   it   is   not   always   obvious   to   the  modern  researcher  that  such  discussions  were  really  about  X  rather  than  Y.    

This   may   apply   to   the   case   at   hand,   at   least   to   some   extent.   Where  exactly  in  their  writings  do  the  scholastics  discuss  powers?  I  believe  they  did  it  under   the  heading  of   this  question:   “is   the  soul   the  same  as   its  powers?”  The  nice  thing  here  is  that  the  question  does  actually  mention  “powers”  (not  all   scholastic  questions  are   so   forthcoming).  Nevertheless,   it   is  not  entirely  obvious  that  the  question  is  about  the  ontology  of  powers.  

The  texts  make  it  clear  that,  in  the  context  of  this  particular  question,  we  can  think  of  the  “soul”  as  the  human  mind,  and  its  “powers”  as  our  cognitive  abilities.   Given   that,   the   question   may   seem   equivalent   to   something   like  this:   “is   the   human  mind   anything   more   than   its   cognitive   abilities?”   And  that  of  course  is  a  perfectly  sensible  question.  We  talk  about  “the  mind”  as  if  it  were  some  sort  of  thing,   some  sort  of   invisible  entity   that  sits   inside  our  heads,   in   roughly   the   same   spot   as   our  brain.  But   is   that   really   true?  Or   is  “the  mind”   just   our   capability   to  perform  certain   cognitive   functions?  That  would  be  one  very  straight  forward  way  of  reading  the  question.  

I   think  the  question  is   indeed  about  that,  but  I  do  not  think  it   is  merely  about  that.  I  believe  the  scholastics  meant  their  answers  to  this  question  to  apply  more  generally  —  to  apply  not  just  to  the  mind  and  its  powers,  but  to  anything  and  its  powers.  The  question  they  were  answering  was  not  just  “is  the   mind   the   same   as   its   powers?”   They   were   also   answering   the   more  general  question:  “is  a  power  the  same  as  its  basis?”  or  “is  a  power  anything  over   and   above   its   basis?”5   To   keep   things   focused,   I   will   restrict   my  

                                                                                                               5  It  is  not  entirely  unwarranted  to  discuss  powers  and  dispositions  in  the  context  of  philosophy  of  mind.  Gilbert  Ryle  said  some  rather  influential  things  about  dispositions  in  The  Concept  of  Mind,  as  did  David  Armstrong  in  A  Materialist  Theory  of  Mind.  And  of  course,  

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discussion   to   these  more   general   questions   about   the   ontology   of   powers,  and  I  will  avoid  questions  about  the  nature  of  the  mind.  Fascinating  as  that  may  be,  it  is  a  topic  for  another  paper.  

   

Thomas  Aquinas    Throughout   his   career,   Aquinas   maintained   that   the   mind   cannot   be  identical  to  its  powers.  He  discussed  the  issue  in  a  number  of  places,  and  he  offered  a  number  of  different  arguments  to  support  this  view.  A  few  of  those  arguments  strike  me  as  incomprehensible,  and  I  admit  that  I  cannot,  for  the  life  of  me,  seem  to  figure  them  out.  Fortunately  for  me,  Aquinas  offered  a  few  arguments  that  do  make  good  sense,  and  they  seem  to  boil  down  to  the  same  basic  point:   I   always  have   a  mind   (so   long   as   I   exist),   but   I   am  not   always  exercising  my  cognitive  powers,  so  those  powers  must  be  different  from  my  mind.6    

This   is,   of   course,   a   simple   argument   from   identity   (or   rather,   the   lack  thereof),   and  we   could   rephrase   it   as   follows.   If   any  A   and  B   are   identical,  then  anything  true  of  the  one  must  be  true  of  the  other.  But  since  this  is  not  the   case   with   my   mind   and   its   powers,   they   must   not   be   identical.   As   I  discussed  earlier,   one  might   say   the   same   thing  about   the   fragility  of  wine  

                                                                                                                                                                                                                                                                                   whether  you  think  the  mind  is  anything  more  than  its  powers  could  easily  depend  on  your  ontology  of  powers  and  dispositions.    6  Aquinas,  Summa  Theologica,  1.77.1.resp.:  “Nam  anima  secundum  suam  essentiam  est  actus.  Si  ergo  ipsa  essentia  animae  esset  immediatum  operationis  principium,  semper  habens  animam  actu  haberet  opera  vitae;  sicut  semper  habens  animam  actu  est  vivum  .  .  .  Unde  quod  sit  in  potentia  adhuc  ad  alium  actum,  hoc  non  competit  ei  secundum  suam  essentiam,  inquantum  est  forma;  sed  secundum  suam  potentiam.  Et  sic  ipsa  anima,  secundum  quod  subest  suae  potentiae,  dicitur  actus  primus,  ordinatus  ad  actum  secundum.  Invenitur  autem  habens  animam  non  semper  esse  in  actu  operum  vitae.  Unde  etiam  in  definitione  animae  dicitur  quod  est  actus  corporis  potentia  vitam  habentis,  quae  tamen  potentia  non  abiicit  animam.  Relinquitur  ergo  quod  essentia  animae  non  est  eius  potentia.  Nihil  enim  est  in  potentia  secundum  actum,  inquantum  est  actus.”  See  also  Summa  Theologica,  1.54.3.resp.:  “Respondeo  dicendum  quod  nec  in  Angelo  nec  in  aliqua  creatura,  virtus  vel  potentia  operativa  est  idem  quod  sua  essentia.  Quod  sic  patet.  Cum  enim  potentia  dicatur  ad  actum,  oportet  quod  secundum  diversitatem  actuum  sit  diversitas  potentiarum,  propter  quod  dicitur  quod  proprius  actus  respondet  propriae  potentiae.  In  omni  autem  creato  essentia  differt  a  suo  esse,  et  comparatur  ad  ipsum  sicut  potentia  ad  actum,  ut  ex  supra  dictis  patet.  Actus  autem  ad  quem  comparatur  potentia  operativa,  est  operatio.  In  Angelo  autem  non  est  idem  intelligere  et  esse,  nec  aliqua  alia  operatio  aut  in  ipso  aut  in  quocumque  alio  creato,  est  idem  quod  eius  esse.  Unde  essentia  Angeli  non  est  eius  potentia  intellectiva,  nec  alicuius  creati  essentia  est  eius  operativa  potentia.”  And  Summa  Theologica,  1.79.1.resp.:  “necesse  est  dicere,  secundum  praemissa,  quod  intellectus  sit  aliqua  potentia  animae,  et  non  ipsa  animae  essentia.  Tunc  enim  solum  immediatum  principium  operationis  est  ipsa  essentia  rei  operantis,  quando  ipsa  operatio  est  eius  esse,  sicut  enim  potentia  se  habet  ad  operationem  ut  ad  suum  actum,  ita  se  habet  essentia  ad  esse.  In  solo  Deo  autem  idem  est  intelligere  quod  suum  esse.  Unde  in  solo  Deo  intellectus  est  eius  essentia,  in  aliis  autem  creaturis  intellectualibus  intellectus  est  quaedam  potentia  intelligentis.”  

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glasses:   fragility   just   cannot   be   the   same   as   the   glass   it   is   based   on,   for  glasses  shatter  only  sometimes  (like  when  I  drop  them).    

We  could  take  this  argument  even  further.  For  we  might  recall  the  point  that  one  of  the  characteristics  of  powers  is  that  they  can  often  be  exercised  only  in  certain  circumstances  —  like  how  wine  glasses  break  not  at  random,  but  when  they  are  dropped,  struck  by  a  fast  moving  baseball  bat,  and  so  on.  We  might   then  point  out   that   each   type  of   cognitive  power   is  no  different:  each  requires  a  different  set  of  circumstances  for  its  exercise  too.    

For  example,   compare  my  power  of   sight  with  my  ability   to   remember  things  I  have  already  seen.  So  far  as  Aquinas  is  concerned,  both  of  these  are  powers   rooted   in  my  mind:   they   are   cognitive   capacities   in   some   sense   or  other.  However,  it  would  seem  that  while  the  former  power  can  be  exercised  in   one   set   of   circumstances   (I   must   have   my   eyes   open,   there   must   be  sufficient  light,  and  so  forth),  the  latter  power  requires  an  entirely  different  set  of  circumstances   (e.g.,   that  what   I   saw  before  was  adequately  stored   in  memory,  and  so  forth).    

Given  that,  we  might  then  make  the  following  inference:  since  each  type  of  cognitive  power  requires  a  different  set  of  circumstances  for  its  exercise,  it   follows   that   each   type   of   cognitive   power   must   be   distinct   from   every  other  type  of  cognitive  power,  and  from  the  mind  it  is  rooted  in.  Otherwise,  I  could  not  exercise  one  of  my  cognitive  powers  without  exercising  all  of  them  at  the  same  time  (it  would  be  like  hooking  all  the  lights  in  your  house  up  to  one  light  switch:  you  couldn’t  flip  the  switch  without  turning  all  the  lights  on  at  the  same  time).  So,  one  might  say,  surely  it  follows  that  my  mind,  and  each  of  its  powers,  must  each  be  distinct  one  from  the  other.7  

If   we   generalize   these   claims   so   that   they   apply   to   all   powers,   the  following  picture  emerges:  powers  must  be  distinct  from  the  things  they  are  based   on,   for   powers   and   their   bases   have   different   identity   conditions.  Again,   wine   glasses   are   always   made   of   glass,   but   they   are   not   always  shattering,  so  glass  and  fragility  cannot  be  one  and  the  same  thing.  Whatever  else  we  might  want  to  say  about  fragility,  considerations  of  identity  push  us  to   conclude   that   it  must   be   a   distinct   thing   over   and   above   the   glass   it   is  

                                                                                                               7  And  Aquinas  would  certainly  agree  that  the  mind’s  powers  are  different.  Summa  Theologiae,  1.77.3.resp.:  “Respondeo  dicendum  quod  potentia,  secundum  illud  quod  est  potentia,  ordinatur  ad  actum.  Unde  oportet  rationem  potentiae  accipi  ex  actu  ad  quem  ordinatur,  et  per  consequens  oportet  quod  ratio  potentiae  diversificetur,  ut  diversificatur  ratio  actus.  Ratio  autem  actus  diversificatur  secundum  diversam  rationem  obiecti.”  See  also  the  Disputed  Questions  on  the  Soul,  12.resp.  (ed.  Robb,  182):  “Deinde  hoc  apparet  ex  ipsa  diversitate  actionum  animae,  quae  sunt  genere  diversae,  et  non  possunt  reduci  ad  unum  principium  immediatum;  cum  quaedam  earum  sint  actiones  et  quaedam  passiones,  et  aliis  huiusmodi  differentiis  differant,  quae  oportet  attribui  diversis  principiis.  Et  ita,  cum  essentia  animae  sit  unum  principium,  non  potest  esse  immediatum  principium  omnium  suarum  actionum;  sed  oportet  quod  habeat  plures  et  diversas  potentias  correspondentes  diversitati  suarum  actionum.  Potentia  enim  ad  actum  dicitur  correlative,  unde  secundum  diversitatem  actionum  oportet  esse  diversitatem  potentiarum.”  

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rooted  in  —  it  must  be  a  unique  kind  of  entity  all  to  its  own  that,  in  a  manner  of  speaking,  is  “attached  to”  or  at  least  “hovers  around”  the  glass.  

What   this   suggests   is   that   Aquinas   has   what   we   might   call   a   “two-­‐category”   ontology:   he   believes   not   just   in   categorical   entities   like   glass,  flames,  and  heat;  he  also  believes  there  is  another  type  of  entity  in  the  world,  namely  powers  and  dispositions,  which  are  distinct  entities  all  to  their  own.  

Nevertheless,  even  if  we  grant  that  powers  and  dispositions  are  distinct  things   that  belong   in   their  own  class,  we   still  might  wonder:  what   sorts  of  things   are   they?  With   regard   to   this   question,   Aquinas   explains   that   every  category  has   its  potential   versions  and   its   actual  versions:   there  are  actual  humans   and   potential   humans;   actual   tans   and   potential   tans;   actual  thoughts  and  potential  thoughts;  and  so  on.8  Powers,  however,  are  really  just  the   potential   versions   of   their   actualizations.9   And   that   means   that   if   we  want  to  figure  out  what  kind  of  thing  a  power  is,  we  only  have  to  figure  out  what  kind  of  thing  its  actualization  is,  because  the  power  for  it  is  just  going  to  be  the  potential  version  of  it.    

So   what   about   mental   powers   —  my   ability   to   think,   for   instance?  According  to  Aquinas,  thoughts  are  qualities  of  the  mind.10  Consequently,  my  power  to  think  must  therefore  just  be  the  potential  version  of  a  thought.  That  is  to  say,  my  “power”  to  have  a  thought  is  really  just  a  potential  thought,  and  when  I  think  that  thought,  it  goes  from  being  a  potential  thought  to  being  an  actual  thought.11                                                                                                                  8  Aquinas,  Disputed  Questions  on  the  Soul,  12.resp.  (ed.  Robb,  181):  “Quia  unumquodque  genus  dividitur  per  potentiam  et  actum.  Unde  potentia  homo  est  in  genere  substantiae,  et  potentia  album  est  in  genere  qualitatis.”  Summa  Theologiae,  1.77.1.resp.  (Marietti  1952,  1:  369b):  “Primo  quia,  cum  potentia  et  actus  dividant  ens  et  quodlibet  genus  entis,  oportet  quod  ad  idem  genus  referatur  potentia  et  actus.  Et  ideo,  si  actus  non  est  in  genere  substantiae,  potentia  quae  dicitur  ad  illum  actum,  non  potest  esse  in  genere  substantiae.”  9  Aquinas,  Disputed  Questions  on  the  Soul,  12.resp.  (ed.  Robb,  181):  “De  potentia  vero  passiva  manifestum  est  quod  potentia  passiva  quae  est  ad  actum  substantialem,  est  in  genere  substantiae;  et  quae  est  ad  actum  accidentalem,  est  in  genere  accidentis  per  reductionem,  sicut  principium,  et  non  sicut  species  completa.”  10  In  fact,  Aquinas  thinks  all  mental  operations  are  accidents  of  some  sort  or  other.  Aquinas,  Scriptum  super  Libros  Sententiarum,  1.3.4.2.resp.  (edited  by  R.  P.  Mandonnet  (Paris:  Lethielleux,  1929):  1:  116;  Opera  Omnia,  edited  by  S.  Frette  and  Paul  Mare  (Paris:  Vives,  1873),  7:  63a)):  “effectus  proprius  et  immediatus  oportet  quod  proportionetur  suae  causae;  unde  oportet  quod  in  omnibus  illis,  in  quibus  principium  operationis  proximum  est  de  genere  substantiae,  quod  operatio  sua  sit  substantia;  et  hoc  solum  in  Deo  est:  et  ideo  ipse  solus  est  qui  non  agit  per  potentiam  mediam  differentem  a  sua  substantia.  In  omnibus  autem  aliis  operatio  est  accidens:  et  ideo  oportet  quod  proximum  principium  operationis  sit  accidens,  sicut  videmus  in  corporibus  quod  forma  substantialis  ignis  nullam  operationem  habet,  nisi  mediantibus  qualitatibus  activis  et  passivis,  quae  sunt  quasi  virtutes  et  potentiae  ipsius.  Similiter  dico,  quod  ab  anima,  cum  sit  substantia,  nulla  operatio  egreditur,  nisi  mediante  potentia.”    11  Aquinas,  Summa  Theologiae,  1.77.1.ad.5:  “si  accidens  accipiatur  secundum  quod  dividitur  contra  substantiam,  sic  nihil  potest  esse  medium  inter  substantiam  et  accidens,  quia  dividuntur  secundum  affirmationem  et  negationem,  scilicet  secundum  esse  in  subiecto  et  non  esse  in  subiecto.  Et  hoc  modo,  cum  potentia  animae  non  sit  eius  essentia,  oportet  quod  sit  

  11  

Now,   to   say   that  powers  are   “qualities”  of   the  mind  might   suggest   that  they  are  properties  or  tropes  that  characterize  the  mind  perhaps  similar  to  the   way   that   a   pale   skin   color   is   one   of   the   qualities   that   characterizes  Socrates.   And   that,   in   turn,   might   suggest   that   the   mind’s   powers   can   be  gained  and   lost,   just   like  the  color  of  Socrates’  skin.  After  all,  Socrates’  skin  color  can  change  —  as  would  happen,   say,   if  he  went   to   the  beach  and  got  himself  a  nice  tan.  And  if  our  cognitive  powers  are  qualities  that  characterize  our  minds,  surely  they  can  change  too.    

But   Aquinas   rejects   this,   insisting   instead   that   although   the   mind’s  powers  are  qualities  of  the  mind,  they  cannot  be  gained  and  lost  in  the  way  that  Socrates’  skin  color  can.  On  the  contrary,  cognitive  powers  are  not  the  sorts   of   features   that   can   “come   and   go.”   Rather,   they   are   permanently  attached,  so  to  speak,  to  the  mind  itself.12    

Be  that  as  it  may,  there  is  a  deep  problem  here,  for  it  is  far  from  clear  just  what  a  potential  thought  or  a  potential  anything  is  really  supposed  to  be.  If  a  power  is  really  just  a  potential  version  of  its  actualization,  what  exactly  does  the   “potential   version”   look   like?   Is   it   a   ghostly   version   of   the   real   thing?  Where   exactly   is   it   located?   Could   we   ever   detect   it   with   laboratory  equipment?  Is  a  “potential  thought”  some  other  thought  that  someone  has  in  another  world?  Aquinas  may  feel  that  considerations  of  identity  force  him  to  postulate   powers   as   a   distinct   class   of   entities   all   to   their   own,   but   the  

                                                                                                                                                                                                                                                                                   accidens,  et  est  in  secunda  specie  qualitatis.”  See  also  the  Disputed  Questions  on  the  Soul,  12.resp.  (ed.  Robb,  181):  “De  potentia  vero  passiva  manifestum  est  quod  potentia  passiva  quae  est  ad  actum  substantialem,  est  in  genere  substantiae;  et  quae  est  ad  actum  accidentalem,  est  in  genere  accidentis  per  reductionem,  sicut  principium,  et  non  sicut  species  complete  .  .  .  Manifestum  est  autem  quod  potentiae  animae,  sive  sint  activae  sive  passivae,  non  dicuntur  directe  per  respectum  ad  aliquid  substantiale,  sed  ad  aliquid  accidentale.  Et  similiter  esse  intelligens  vel  sentiens  actu  non  est  esse  substantiale,  sed  accidentale,  ad  quod  ordinatur  intellectus  et  sensus.”  12  Aquinas,  Summa  Theologiae,  1.77.1.ad.5:  “Si  vero  accipiatur  accidens  secundum  quod  ponitur  unum  quinque  universalium,  sic  aliquid  est  medium  inter  substantiam  et  accidens.  Quia  ad  substantiam  pertinet  quidquid  est  essentiale  rei,  non  autem  quidquid  est  extra  essentiam,  potest  sic  dici  accidens,  sed  solum  id  quod  non  causatur  ex  principiis  essentialibus  speciei.  Proprium  enim  non  est  de  essentia  rei,  sed  ex  principiis  essentialibus  speciei  causatur,  unde  medium  est  inter  essentiam  et  accidens  sic  dictum.  Et  hoc  modo  potentiae  animae  possunt  dici  mediae  inter  substantiam  et  accidens,  quasi  proprietates  animae  naturales.”  Cf.  Aquinas’s  Disputed  Questions  on  the  Soul,  12.resp.  (ed.  Robb,  181-­‐182):  “Manifestum  est  ergo  quod  ipsa  essentia  animae  non  est  principium  immediatum  suarum  operationum,  sed  operatur  mediantibus  principiis  accidentalibus;  unde  potentiae  animae  non  sunt  ipsa  essentia  animae,  sed  proprietates  eius.”  Aquinas,  Scriptum  super  Libros  Sententiarum,  1.3.4.2.resp.:  “Hae  autem  potentiae  fluunt  ab  essentia  ipsius  animae,  quaedam  ut  perfectiones  partium  corporis,  quarum  operatio  efficitur  mediante  corpore,  ut  sensus,  imaginatio  et  hujusmodi;  et  quaedam  ut  existentes  in  ipsa  anima,  quarum  operatio  non  indiget  corpore,  ut  intellectus,  voluntas  et  hujusmodi;  et  ideo  dico,  quod  sunt  accidentia:  non  quod  sint  communia  accidentia,  quae  non  fluunt  ex  principiis  speciei,  sed  consequuntur  principia  individui;  sed  sicut  propria  accidentia,  quae  consequuntur  speciem,  originata  ex  principiis  ipsius:  simul  tamen  sunt  de  integritate  ipsius  animae,  inquantum  est  totum  potentiale,  habens  quamdam  perfectionem  potentiae,  quae  conficitur  ex  diversis  viribus.”  

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downside   is   that   this   distinct   class   of   entities   remains   completely  mysterious.    

   

Henry  of  Ghent    

Henry  of  Ghent  rejects  Aquinas’s  theory  for  the  simple  reason  that  it  cannot  be  generalized.  As  Henry  sees  it,  it  just  cannot  be  the  case  that  every  power  or  disposition  is  distinct  from  its  basis,  for  if  that  were  so,  we  would  end  up  with  an   infinite   regress.   Suppose   that  a  power  or  disposition  were  distinct  from  its  basis.  What  would  dispose  the  basis   to  be  disposed   in   that  way?  A  further  power  or  disposition?  And  if  that  further  power  or  disposition  were  also   distinct,   what   would   dispose   the   basis   to   it?   Yet   another   power   or  disposition?   We   cannot   keep   saying   that   one   disposition   is   explained   by  another  disposition,  for  that  would  never  explain  anything.  It  would  be  like  paying   a   bounced   check   with   another   bounced   check:   you   would   never  actually   pay   anything.   So,   Henry   concludes,   there   must   be   at   least   some  powers  and  dispositions  that  are  the  same  as  their  bases.13    

Henry  offers  a  number  of  different  examples   to  buttress   this  point.  For  instance,  consider  the  basic  matter  that  makes  up  the  universe.  At  the  most  fundamental   level   of   decomposition,   the   basic   matter   of   the   universe   is  capable  of  being  formed  and  organized  into  various  other  kinds  of  stuff.  As  we  might  put   it   today:  under   the  right  conditions,  you  can  get  amino  acids  and  proteins,  helium  and  hydrogen,  and   lots  of  other  sorts  of   things  out  of  the  universe’s  matter,  so  surely  the  basic  matter  of  the  universe  is  capable  of  being  formed  and  organized  into  these  various  kinds  of  substances.    

Of  course,  the  scholastics  did  not  know  about  amino  acids  and  proteins,  helium  and  hydrogen,  but  they  did  think  matter  could  be  formed  into  other  primitive   kinds   of   stuff   like   fire,   air,  water,   and  dirt,   so   the   general   idea   is  still   the   same.   And   the   salient   point   here   is   this:   when   it   comes   to   the  capacity   of   matter   to   be   formed   and   organized   into   various   kinds   of  substances  —  that  capacity  is  a  disposition  or  power.  Matter  is  disposed,  we  might   say,   to   be   formed   and   organized   in   certain   ways   under   certain  conditions,   much   like   how   a   wine   glass   is   disposed   to   shatter   under   a  different  set  of  conditions.    

Furthermore,  one  might  think,  surely  that  disposition  must  be  based  on  other,  more   fundamental,   characteristics   of  matter.   Perhaps   there   are   sub-­‐                                                                                                                13  To  pull  just  two  quotations  from  Henry’s  Quodlibet  3.14  that  run  to  this  effect  (Bad.  I,  f.  67rR):  “Si  enim  esset  potentia  illa  alia  re  ab  ipsa  essentia,  illa  accidens  esset  in  illa  essentia  quae  eius  esset  receptiva,  et  hoc  non  nisi  per  potentiam  passivam  quae  est  ipsa  essentia,  vel  esset  abire  in  infinitum,  ut  dictum  est;”  and  (Bad.  I,  f.  66vQ):  “Similiter  si  aliquid  sit  natum  agere  ex  se  et  secundum  se,  sed  non  sine  adminiculo  alterius,  vel  eius  in  quod  agit,  vel  eius  quo  agit,  non  oportet  quod  aliud  sit  essentia  eius,  et  aliud  potentia  qua  agit.  Et  tamen  actio  non  est  ipsa  substantia,  nec  oportet  quod  semper  sit  in  sua  actione.  Exemplum  de  primo  est  in  calore  .  .  .  Exemplum  de  secundo  est  in  operibus  animae  intellectivae,  ut  iam  patebit.”  

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atomic   characteristics   of   matter   that   dispose   it   to   being   formed   and  organized   in   the   various   ways   that   it   gets   formed   and   organized,   but  whatever  the  case,  surely  there  is  something  about  the  intrinsic  make-­‐up  of  matter  that  disposes   it   to  being  formed  and  organized  in  so  many  different  ways.    

Even  still,  the  question  is  whether  or  not  the  disposition  to  be  formed  in  so  many  ways   is   distinct   from   the  basis   for   it.   Is   the   disposition   a   distinct  entity   in   its   own   right,   some   sort   of   distinct   “thing”   that   is   somehow  “attached,”  so  to  speak,  to  matter?    

If  Aquinas’s  general  theory  were  applied  to  this  case,  the  answer  would  have  to  be  yes:  the  disposition  to  be  formed  in  so  many  ways  must  be  distinct  from   the  basis   for   it,   and   again,   the   reason  would   be   that   if   they  were   the  same,  then  anything  true  of  the  one  would  have  to  be  true  of  the  other,  but  that  is  not  the  case.  After  all,  matter  is  always  matter,  and  so  for  the  duration  of  its  lifespan  it  has  the  very  sub-­‐atomic  characteristics  that  dispose  it  to  be  formed  and  organized   in  different  ways  (and   that,  presumably,   is  precisely  what  makes  it  the  most  fundamental  kind  of  “matter”).  Nevertheless,  matter  is  not  always  being  formed  and  organized  in  this  way  or  that  way,  and  so  it  would   seem   that   the   disposition   to   be   formed   in   a   variety   of   ways   simply  cannot  be  identical  to  the  sub-­‐atomic  basis  for  it.  

But  Henry  would  ask:  if  the  disposition  in  question  were  a  distinct  thing  in  its  own  right  —some  sort  of  external  entity  hovering  about  —  what  would  dispose  matter   to   it?   If   it  were   truly  distinct,  and  hence  external   to  matter,  then  why  should  it  “hang  around”  matter,  perhaps  in  the  way  that  electrons  “hang   around”   protons   and   neutrons?  What   is   it   about  matter   that   would  attract   it,   so   to   speak?   Wouldn’t   it   have   to   be   a   further,   perhaps   more  fundamental,   disposition   of   matter?   But   then   that   disposition   would   be  distinct  too,  so  what  would  dispose  the  matter  to  it?  Yet  another,  even  more  fundamental   disposition?14   We   cannot   go   on   forever,   says   Henry,   so   we  might   as   well   just   assume   from   the   start   that   matter’s   capability   to   be  

                                                                                                               14  One  might  think  that  Aquinas’s  theory  cannot  be  applied  to  this  case  (namely,  to  the  most  basic  kind  of  matter  in  the  universe),  for  Aquinas  explicitly  claims  that  when  it  comes  to  this  fundamental  or  basic  sort  of  matter,  its  disposition  to  be  formed  into  various  kinds  of  substances  is  not  distinct  from  its  basis.  As  he  puts  it  in  ST  1.77.1.ad.2  (Marietti  1952,  1:  370a):  “Ad  secundum  dicendum  quod  actus  ad  quem  est  in  potentia  material  prima,  est  substantialis  forma.  Et  ideo  potentia  materiae  non  est  aliud  quam  eius  essentia.”  However,  Aquinas  only  says  this  because  he  believes  that,  at  the  most  fundamental  level,  “matter”  is  really  just  this  disposition  to  be  transformed  into  various  kinds  of  substances.  To  use  the  old  Thomistic  tagline:  for  Aquinas  matter  is  the  “pure”  —  or  better  mere  —  “potentiality”  to  be  formed  and  organized  into  various  other  kinds  of  substances.  Consequently,  Henry’s  argument  still  applies  —  it  just  applies  to  things  that  have  this  matter-­‐like  disposition:  for  we  could  still  ask,  what  makes  them  disposed  in  this  matter-­‐like  way?  Is  it  a  further  disposition?  Again,  Henry  would  say  that  we  cannot  go  on  ad  infinitum.    

  14  

formed  into  other  kinds  of  stuff  is  not  some  distinct  thing  over  and  above  the  basis  for  that  capability.15    

Another  example  Henry  mentions  concerns  flames.  Flames  can  of  course  heat  other   things,   and  according   to  most  medieval   accounts,   this  power  or  ability  of  flames  is  based  on  their  heat:  it  is  the  heat  in  a  flame  that  makes  it  capable  of  heating  other   things.  But   is  a   flame’s  ability   to  heat  other   things  distinct   from   its   heat?   If   Aquinas’s   general   theory   were   applied   here,   the  answer   would   again   have   to   be   yes:   the   ability   to   heat   would   have   to   be  something  distinct  from  the  heat  itself,  for  flames  are  always  hot  even  if  they  are  not  always  heating  other  things.  But  again  Henry  asks:  if  a  flame’s  ability  to  heat  other  things  were  genuinely  distinct  from  the  heat  in  the  flame,  if  it  were   truly   some  external  entity   that   “hung  around”  heat,   then  what  would  attract  it  to  heat?  A  further  power  or  disposition  of  heat?  We  cannot  go  on  ad  infinitum.16    

Henry  does  not  explicitly  apply  this  line  of  argument  to  the  powers  of  the  mind,  but  he  must  have  thought  it  so  obvious  that  there  was  no  need  to  spell  it   out.   He   clearly   intended   his   reasoning   to   be   taken   as   a   refutation   of  Aquinas’s   position.17   So,   for   instance,   Henry   could   argue   like   this:   if   the  mind’s  capacity  for  a  thought  were  a  distinct  thing  “attached,”  so  to  speak,  to  the   mind   itself   (as   Aquinas   claims),   then   what   would   explain   the   mind’s  capacity  for  that  capacity?  A  further,  perhaps  more  fundamental,  capacity  of  the  mind?  But  then  what  would  explain  the  mind’s  capacity  for  that  further  capacity?  Yet  another  capacity  of  the  mind?  We  cannot  go  on  forever,  so  we  might   as   well   assume   from   the   start   that   the   mind’s   capabilities   are   not  distinct  from  whatever  aspect  of  the  mind  they  are  based  on  or  rooted  in.    

                                                                                                               15  Henry  of  Ghent,  Quod.,  3.14  (Bad.  I,  f.  66vR-­‐66rR):  “Potentia  vero  passiva  primo  et  per  se  invenitur  in  prima  materia,  in  qua  sua  potentia  passiva  ita  est  pura  quod  est  ipsa  essentia  materiae  sub  sola  ratione  respectus  ad  formam,  qui  nullum  rem  apponit,  neque  compositionem  aliquam  in  re,  quia  si  in  aliqua  re  absoluta  differret  potentia  ab  essentia  materiae,  esset  accidens  et  forma  in  materia,  cuius  proculdubio  materia  esset  receptiva,  et  in  potentia  ad  eam,  et  de  illa  potentia  esset  eadem  quaestio.  Et  procederet  in  infinitum,  nisi  pura  essentia  materiae  assumpto  quodam  respectu  esset  ipsa  sua  potentia  passiva,  non  aliquod  accidens  eius.  Aliter  enim  materia  non  esset  potentia  per  se,  sed  per  aliquid  sui.”  16  Henry,  Quod.,  3.14,  (Bad.  I,  f.  66vP):  “Quia  tamen  aliqua  natura  creata  sit  ex  sua  essentia  potentia  calefaciendi,  ibi  non  est  aliud  essentia  ipsius  caloris,  quae  est  passibilis  qualitas,  et  aliud  ipsa  potentia,  immo  ipsa  essentia  caloris  est  ipsa  potentia  calefaciendi  in  igne.  Non  aliquid  additum  ei  naturalitur,  aliter  enim  esset  abire  in  infinitum,  nisi  esset  stare  in  aliquo  quo  aliud  agit  quod  in  essentia  sua  est  ipsa  potentia.  Quia  si  potentia  non  esset  re  essentia  ipsa,  esset  re  aliquid  additum  ei.  Et  de  illa  re  esset  quaestio  eadem:  utrum  esset  potentia  qua  aliud  ageret.  Quod  si  negaretur,  quaestio  illa  procederet  in  infinitum,  ut  patet.”  17  I  should  note  that  in  this  context  (Quodlibet  3.14),  Henry  quotes  extensively  from  Aquinas’s  Disputed  Questions  on  the  Soul,  article  12,  but  not  from  any  of  Aquinas’s  other  writings.  In  fact,  Henry’s  quotations  from  this  text  by  Aquinas  are  so  lengthy  and  exact  that  I  think  we  can  assume  Henry  had  a  transcript  of  the  text  before  him  when  he  composed  Quodlibet  3.14  —  or,  at  the  very  least,  Henry  must  have  memorized  Aquinas’s  text  at  some  point  prior  to  composing  Quod.,  3.14.    

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I  should  note  that  so  far  in  his  argument,  Henry  is  only  talking  about  the  extension  of  the  concept  of  “power.”  That  is  to  say,  he  is  not  yet  talking  about  the  essence  or  definition  of  power.  Rather,  he  is  simply  talking  about  which  items  in  the  world  our  notion  of  “power”  refers  to  or  picks  out.  And  his  point  here  is  that,  contra  Aquinas,  the  notion  of  “power”  or  “disposition”  does  not  pick  out  some  distinct  thing  over  and  above  the  basis  itself.  Rather,  our  talk  about  powers  and  dispositions  picks  out   the  bases   themselves  —  that   is   to  say,  whatever  parts,  materials,  or  other  constituents  the  powers  in  question  are  based  upon.  So,  whereas  Aquinas’s  theory  postulates  powers  as  distinct  items  that  really  exist  out  there  in  the  world,  Henry  refuses  that.  For  Henry,  there  are  no  distinct  items  out  there  over  and  above  the  parts,  materials,  and  other  constituents  that  make  up  the  thing  in  question.  

Still,  what  about  the  essence  or  definition  of  powers?  With  regard  to  this,  Henry  insists  that  the  notion  of  a  power  is  different  from  that  of  its  basis.  In  particular,  the  notion  of  a  power  or  a  disposition  involves  some  reference  to  the   activity   it   is   a   power   or   disposition   for.18   And   indeed,   as   I   mentioned  earlier,   there  does  seem  to  be  a  close  conceptual   link  between  powers  and  their  exercise.  When  we  think  about  fragility,  we  think  about  shattering,  and  for  good  reason:  shattering  seems  essential  to  the  concept.  It  wouldn’t  be  a  concept  of   fragility  without   it,   for   fragility   is   a  disposition   to   shatter   under  certain  conditions.    

By   contrast,   the   bases   of   powers   and   dispositions   —  the   parts   and  materials  things  are  made  from  —  do  not  seem  to  require  this  kind  of  close  connection   with   the   activities   in   question.   For   instance,   it   seems   entirely  possible   to  conceive  of   (and  perhaps  even  define)  glass  simply   in   terms  of,  say,  its  molecular  structure,  without  any  need  to  reference  shattering.  But  it  it  seems  impossible  to  define  fragility  without  some  reference  to  shattering.  

Henry   thinks   this   is   important,   for   it   suggests   that   the   link   between  powers  and  their  exercise  is  not  just  a  conceptual  link.  Rather,  it  is  a  defining  mark  that  rests  at  the  very  heart  of  what  it  is  to  be  a  power.19  For  Henry,  the  

                                                                                                               18  Henry,  Summa  Quaestionum  Ordinariarum,  35.4  (Opera,  28:  37.76–77):  “Et  quia  omnis  potentia,  in  quantum  potentia,  fundatur  in  aliquo  ut  respectus  ad  aliud.”  And  more  generally,  Henry  maintains  that  being  a  source  implies  a  connection  with  that  for  which  it  is  the  source,  ibid.,  (Opera,  28:  37.67–69):  “quia  principium  ut  principium  non  dicitur  secundum  substantiam,  sed  solum  secundum  relationem,  et  relationem  importat  ad  aliud,  ut  ad  principiatum.”  19  Henry,  Quod.,  3.14  (Bad.  I,  f.  68rY):  “Potentia  enim  non  definitur  nisi  ex  relatione  ad  actum;”  ibid.,  (Bad.  I  f.  70rB):  “Potentia  enim  id  quod  est  dicitur  ex  relatione  ad  actum,  quae  ex  obiectis  sumit  species”;  Summa  Quaestionum  Ordinariarum,  35.8  (Opera,  28:  78.57):  “potentia  significat  ‘ad  aliquid’  [viz.  ad  actum],  et  a  ratione  respectus  imponitur.”  And  as  Henry  also  says  of  the  mind,  Quod.,  3.14  (Bad.  I,  f.  70rB):  “Potentia  enim  id  quod  est  dicitur  ex  relatione  ad  actum,  quae  ex  obiectis  sumit  species:  anima  autem  ex  natura  substantiae  suae  absolutae,  ut  substantia  est,  non  determinat  sibi  actum,  sicut  neque  materia  formam,  quare  neque  rationem  potentiae.  Oportet  igitur  ad  determinationem  potentiae  in  ea  eam  aliquo  determinari,  ut  determinate  ad  actum  determinatum  habeat  respectum,  et  per  hoc  rationem  potentiae.”  

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essence  of  a  power  consists  precisely  in  its  connection  with  the  activities  for  which  it  is  a  power.20  As  he  puts  it:    

 “Regarding   the   nature   of   a   power   (insofar   as   it   is   a   power),   it   is  something   that   is   spoken   of   with   respect   to   some   activity,   so   it   is   not  some  absolute  thing,  but  rather  just  this  connection  with  activity  that  is  based  on  the  absolute  thing.”21  

 Consequently,   Henry   believes   that   when   we   talk   about   powers,   we   are  referring   to   or   picking   out   the   parts,   materials,   and   other   constituents   of  things  only  insofar  as  they  are  linked  to  the  activities  for  which  they  are  the  basis.   Again,   I   can   talk   about   glass,   or   I   can   talk   about   the   fact   that   it   is  fragile,  but  these  are  different  in  a  certain  respect.  For  considered  in  and  of  itself,  glass  is  just  glass:  it  is  a  certain  kind  of  material,  with  a  certain  kind  of  molecular  structure.  But  glass  is  fragile  only  insofar  as  it  shatters.22  

Nevertheless,   I   am   still   referring   to   the   glass   when   I   talk   about   its  fragility.  Again,  contra  Aquinas,  Henry  maintains  that  our  talk  about  powers  does  not  refer  to  some  extra  entity  over  and  above  the  basis  itself.23  So  when  

                                                                                                               20  Another  way  to  put  this  point  of  Henry’s  is  to  say  that  we  speak  about  powers  with  two-­‐place  predicates:  X  has  the  power  to  Y,  X  is  disposed  to  Y,  and  so  on.  But  for  Henry,  this  is  not  just  a  linguistic  or  conceptual  peculiarity;  it  is  not  just  a  feature  of  the  way  that  we  talk  about  powers  or  the  way  that  we  think  about  powers.  On  the  contrary,  Henry  thinks  this  tells  us  about  the  very  nature  of  powers.  By  Henry’s  reckoning,  we  have  to  speak  about  powers  with  two-­‐place  predicates  precisely  because  powers  essentially  involve  a  connection  with  the  activities  for  which  they  are  powers.    21  Henry,  Summa  Quaestionum  Ordinariarum,  35.2  (Opera  Omnia,  28:  15.62-­‐64):  “de  ratione  potentiae  in  quantum  potentia,  est  quod  dicatur  ad  actum,  ita  quod  nihil  absolutum  sit,  sed  solus  respectus  fundatus  in  re  super  aliquo  absoluto.”  22  Or,  to  use  Henry’s  example,  heat  is  just  heat  when  we  consider  it  in  and  of  itself.  It  is  the  basis  for  heating  other  things  only  insofar  as  it  actually  does  so.  Quod.,  3.14  (Bad.  I,  f.  81rF):  “Sicut  caliditas  separata  si  esset  calefactiva  in  se,  non  esset  nisi  qualitas  per  essentiam,  et  non  esset  potentia  quaedam  nisi  ex  naturali  determinatione  et  respectu  ad  actum  calidi:  ita  quod  iret  in  actum  quandocumque  approximaretur  calefactibili,  et  cessaret  ab  actu  absente  calefactibili.”  And  he  goes  on  to  make  the  same  point  about  mental  powers.  Ibid.  (Bad.  I,  f.  81rF):  “dicendum  quod  voluntas  est  potentia  naturalis  in  anima,  et  non  est  nisi  substantia  animae,  sed  ex  naturali  determinatione  et  respectu  ad  actum  volendi  bonum  .  .  .  cum  ei  praesentetur  in  cognition  .  .  .  et  cum  bonum  ut  obiectum  et  materia  ei  non  praesentetur,  velle  secundum  actum  omnino  non  potest.  Similiter  intellectus  agens  potentia  naturalis  est  in  anima,  et  non  est  nisi  substantia  animae:  sed  ex  naturali  determinatione  et  respectu  ad  actum  abstrahendi  species  intelligibiles  a  phantasmate,  cum  ei  praeponuntur,  ita  quod  non  potest  illas  non  abstrahere.”  23  As  Henry  says  of  the  mind  in  Quod.,  3.14  (Bad.  I,  f.  68rY),  the  mind  is  all  we  need  to  refer  to  when  we  talk  about  mental  powers:  “Sic  ergo  dicitur  substantia  animae  eius  potentia:  quia  sine  omni  alterius  adminiculo  habeat  in  sua  essentia  determinate  rationem  potentiae  qua  prosiliat  in  actionem,  immo  ut  ipsa  essentia  eius  determinate  habeat  rationem  alicuius  potentiae  et  determinati  respectus  ad  aliquam  actionem,  oportet  quod  hoc  habeat  ab  aliqua  ipsius  essentiae  determinatione  qua  ad  actum  determinatum  inclinetur.”  

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I   talk   about   fragility,   I   am   still   referring   to   the   glass  —  it’s   just   that   I   am  referring  to  the  glass  insofar  as  it  is  connected  to  shattering.24    

Moreover,  it  is  precisely  that  connection  that  “makes”  or  constitutes  the  glass   as   the  basis   for   shattering.25   It   is   almost   as   if  Henry   is   saying   that   of  course   glass   is   just   glass   (in   and   of   itself),   but   when   you   add   in   that  “connection”   with   shattering,   it   then   becomes   fragile.   In   fact,   Henry   even  goes  so  far  to  say  that  we  can  think  of  powers  in  terms  of  matter  and  form,  where   the   basis   plays   the   role   of   matter   and   the   connection  with   activity  plays   the   role   of   the   form.   Hence,   the   connection  with   shattering   is   like   a  “form”   that   makes   the   glass   fragile,   much   like   how   a   statue   shape   is   the  “form”  that  makes  a  lump  of  bronze  a  statue.26    

In   the   end   then,   Henry   seems   to   propose   that   the   parts   and  materials  that  things  are  made  from  can  serve  both  as  categorical  constituents  and  as  dispositional   constituents.   For   taken   in   themselves,   glass   is   just   glass,   and  heat   is   just   heat.   But   taken   as   they   are   connected   with   shattering   and  heating,  they  are  dispositions  and  powers.27  Thus,  while  Aquinas  has  a  “two-­‐

                                                                                                               24  I  am  not,  Henry  would  say,  referring  to  some  “connection”  that  somehow  stretches  between  the  basis  and  the  activity  in  question.  This  is  because  Henry  does  not  believe  that  relationships  are  things  that  stretch  between  other  things.  For  Henry,  when  we  talk  about  relationships  we  are  referring  to  or  picking  out  their  bases  too.  For  more  on  Henry’s  ontology  of  relations,  see  Mark  Henninger,  Relations:  Medieval  Theories  1250–1325  (Oxford:  Clarendon  Press,  1989),  40–58.  25  This  point  comes  out  clearly  when  Henry  distinguishes  between  the  mind’s  mental  and  sentient  powers:  the  mind  is  one  thing,  but  it  is  “determined”  to  mental  or  sentient  activities  by  its  connections  with  those  activities.  Quod.,  3.14  (Bad.I,  f.  67rS):  “Aut  etiam  accidet  ei  quod  fiat  agens  in  actu,  quia  indiget  ut  determinetur  aliquo  quo  fiat  in  eo  potentia  ad  eliciendum  actionem  determinatam  circa  determinatum  obiectum.  Sicut  contingit  in  actionibus  animae  intellectivis  vel  sensitivis  ad  quas  non  habet  anima  ex  nuda  essentia  sua  aliquas  potentias  determinatas  nisi  aliquo  alio  determinetur  quo  respiciat  determinatum  obiectum  et  determinatam  actionem.  Ita  quod  eius  substantia  quae  una  est  secundum  rem,  secundum  diversa  esse,  et  secundum  diversas  determinationes,  sortitur  rationes  diversarum  potentiarum  intellectivarum  et  sensitivarum,  cum  in  radice  nihil  sit  potentia  in  eadem  nisi  eius  simplex  substantia,  quae  in  se  considerata,  essentia  sive  substantia  est  et  forma  animati,  considerata  vero  secundum  diversa  esse  per  diversas  determinationes  et  operationes  ad  diversas  actiones,  et  ad  diversa  obiecta,  dicitur  potentiae  diversae  quae  non  ponunt  super  essentiam  eius  nisi  solum  respectum  ad  diversos  actus  specie.”  26  Henry,  Summa  Quaestionum  Ordinariarum,  35.8  (Opera,  28:  78.66-­‐70):  “Potentia  vero  significat  ut  proprietas  ad  aliquid  respiciens,  quod  in  suo  significato  includit  essentiam  sub  ratione  illius  proprietatis,  ut  suum  significatum  sit  quasi  compositum  ex  duobus,  scilicet  ex  ipso  subsistenti,  quod  significat  quasi  materialiter,  et  illa  proprietate,  quam  significat  quasi  formaliter.”  Actually,  Henry  suggests  that  we  can  think  of  any  categorical  entity  that  has  a  connection  with  something  else  like  this.  Ibid.,  32.5  (Opera,  27:  81.57–60):  “Intentio  ergo  praedicamenti  constituitur  ex  re  naturae  subiecta,  quae  est  res  praedicamenti,  quasi  materiale  in  ipso,  et  modo  quo  esse  ei  convenit  .  .  .  quae  est  ratio  praedicamenti  circa  rem  ipsam,  quasi  formale  in  ipso.”  27  Again,  as  Henry  says  of  the  mind’s  powers,  Quod.,  3.14  (Bad.  I,  f.  68vZ):  “Sic  ergo  quod  tanta  est  diversitas  et  distinctio  potentiarum  animae,  hoc  non  est  propter  aliquam  diversitatem  realem  quam  habent  ipsae  ex  parte  animae,  sed  propter  diversitatem  de  terminationum  substantiae  animae  solummodo  diversos  actus  respicit,  et  ex  hoc  nomina  diversarum  

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category”  ontology,  Henry  has  what  we  might  call  a  “two-­‐aspects”  ontology:  there  aren’t  two  entirely  separate  classes  of  things,  there’s   just  one  class  of  things,  but  nevertheless,  the  parts,  materials,  and  other  constituents  that  fall  into   that   one   class   can   have   both   a   categorical   aspect   and   a   dispositional  aspect.28  

   

John  Duns  Scotus    

Like   Henry,   Scotus   rejects   Aquinas’s   view   that   powers   are   distinct   things  over  and  above  their  bases,  for  much  the  same  reason:  if  every  power  were  distinct   from   its   basis,   we   would   end   up   with   an   infinite   regress,   and   we  would   not   be   able   to   explain   what   ultimately   disposes   bases   to   their  powers.29  But  Scotus  also  rejects  Henry’s  claim  that  bases  essentially  include  a  connection  with  their  activities.    

It  is  important  to  be  clear  on  what  Scotus  is  objecting  to  here.  He  is  not  denying   that   there   are   connections   between   bases   and   their   activities.   On  the  contrary,  Scotus   is  happy   to  admit   that   there  are   such  connections.   If   I  

                                                                                                                                                                                                                                                                                   potentiarum  sortitur:  ut  dicatur  potentia  intellectiva  ex  comparatione  quam  habet  ad  operationem  quam  secundum  se  habet  elicere”;  ibid.,  (Bad.  I,  f.  69rZ):  “Sed  in  eodem  in  quo  tantum  est  una  anima  secundum  substantiam,  ut  dictum  est  supra,  re  sunt  idem  omnes  partes  [viz.,  potentiae  animae],  et  non  addit  pars  super  identitatem  rei  in  toto  nisi  respectum  quemdam,  et  in  hoc  solummodo  pars  una  dicitur  alia  ab  alia,  quod  alium  et  alium  notat  respectum,  ut  dictum  est”;  ibid.,  (Bad.  I,  f.  81rE):  “Et  sic  omnes  [diversae  potentiae]  accidunt  essentiae  eius,  non  quia  sunt  re  aliquid  ab  ea,  sed  quia  est  respectus  ei  additus  extra  intentionem  essentiae  suae,  sicut  primae  materiae  accidunt  potentiae  ad  formas.”  28  For  more  on  a  “two-­‐aspects  ontology,”  see  (for  instance)  the  classic  paper  by  D.  H.  Mellor,  “In  Defense  of  Dispositions,”  The  Philosophical  Review  83  (1974):  157-­‐181.  For  further  discussion  on  Henry’s  theory  of  powers,  as  well  as  Aquinas’s  and  Scotus’s,  see  Richard  Cross,  “Accidents,  Substantial  Forms,  and  Causal  Powers  in  the  Late  Thirteenth  Century:  Some  Reflections  on  the  Axiom  ‘actiones  sunt  suppositorum’,”  in  Compléments  de  substance:  Etudes  sur  les  propriétés  accidentelles  offertes  à  Alain  de  Libera  (Paris:  Vrin,  2008),  133–46.  For  more  on  Henry’s  ontology  of  powers  specifically,  see  my  Divine  Production  in  Late  Medieval  Trinitarian  Theology  (Oxford:  Oxford  University  Press,  2012),  ch.  9.  29  Scotus,  Ord.,  2.16,  n.  46  (ed.  Garcia,  2:  580):  “Praeterea,  aliquis  actus  vel  aliqua  forma  inferior  anima  potest  esse  principium  immediatum  agendi.  Patet  de  calore  et  qualitatibus  activis;  aliter  esset  processus  in  infinitum.”  I  should  also  note  that  Scotus  seems  to  be  dealing  with  Aquinas  through  the  eyes  of  Henry  of  Ghent.  That  is  to  say,  in  Quodlibet  3.14,  Henry  quotes  Aquinas’s  Disputed  Questions  on  the  Soul,  article  12  directly.  But  Scotus  then  seems  to  quote  from  Henry  directly,  and  Ockham  seems  to  quote  either  from  Scotus  or  Henry.  It  would  seem  then,  that  Aquinas’s  theory  of  powers  comes  to  Scotus  and  Ockham  entirely  through  Henry,  who  was  looking  only  at  Aquinas’s  Disputed  Questions  on  the  Soul,  article  12.  I  do  not  think  the  scholarship  has  appreciated  this  point.  For  instance,  the  editors  of  both  Scotus’s  and  Ockham’s  critical  editions  try  to  locate  the  quotations  from  Aquinas  in  the  Summa,  but  that  isn’t  right  (which  is  clear  from  the  fact  that  what  Scotus  and  Ockham  quote  doesn’t  match  the  texts  cited  by  the  editors  in  the  ad  fontes).  The  quotations  we  find  in  Scotus  and  Ockham  come  verbatim  from  Aquinas’s  Disputed  Questions  on  the  Soul,  article  12,  so  it  seems  highly  likely  that  Scotus  and  Ockham  are  getting  those  quotations  straight  from  Henry’s  Quodlibet  3.14.    

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dropped  my  wine  glass  and  it  shattered,  Scotus  would  be  perfectly  happy  to  point   out   that   there   is   a   real   connection   there   between   the   glass   and   the  shattering:   the   glass   really   does   shatter.   Scotus   does   not   have   a   problem  with  the  connection  itself.30    

What   Scotus   has   a   problem   with   is   the   notion   that   these   sorts   of  connections   could   be   essential   to   bases,   that   they   could   play   some   kind   of  constitutive   role   in   bases.  And   the   reason   Scotus   gives   is   this:   connections  presuppose   the   things   they   connect,   not   the   other   way   around,   and   so   no  connection   could   ever   be   an   essential   part   of   whatever   it   connects.   That  would   be   like   saying   that   having   children   makes   parents   fertile,   which   is  clearly   false   because   parents   must   be   fertile   in   order   to   have   children.  Having   children  may  be  a   sign  of   their   fertility,   but   it   cannot  be   the   cause.  Likewise,   the   connection   between   glass   and   shattering   may   be   a   sign   of  glass’s  fragility,  but  it  cannot  be  part  of  the  cause.31    

To   make   this   point,   Scotus   employs   some   technical   terminology:  connections,  he  says,  are  “naturally  posterior”  to  the  things  they  relate,  not  “natural  prior”  to  them,  and  for  Scotus  one  thing  is  naturally  prior  to  another  if  the  first  can  exist  without  the  second,  but  not  vice  versa.32  This  applies  to                                                                                                                  30  That  Scotus  is  happy  to  admit  these  connections  is  clear  from  the  following.  Meta.,  9.5,  n.  12  (OPh  4:  562.19–22):  “Ideo  dicitur  aliter  ad  quaestionem  quod  cum  relatio,  quam  importat  hoc  nomen  ‘potentia’  .  .  .  simul  sit  natura  cum  relatione  principiati  actu,  actu,  et  potentia,  potentia”;  ibid.,  9.3–4,  n.  19  (OPh  4:  542.13–14):  “Patet  itaque  quod  principium  importat  essentialiter  relationem  principiationis”;  ibid.,  n.  20  (OPh  543.9–10):  “Consimiliter  omnino  dicendum  est  de  potentialitate,  potentia  et  potente,  quod  eandem  relationem  important”;  ibid.,  n.  25  (OPh  4:  545.3–5):  “Sciendum  tamen,  secundo,  quantum  ad  istum  articulum,  quod  principium  non  tantum  habet  relationem  ad  principiatum,  et  tale  principium  ad  tale  principiatum  .  .  .  ”  See  also  ibid.,  n.  19  (OPh  4:  542.1–543.8).  31  Scotus,  Meta.,  9.5,  n.  12  (OPh,  4:  562.19-­‐23):  “Ideo  dicitur  aliter  ad  quaestionem  quod  cum  relatio,  quam  importat  hoc  nomen  ‘potentia’  (sicut  patet  ex  solutione  tertiae  quaestionis),  simul  sit  natura  cum  relatione  principiati  actu,  actu,  et  potentia,  potentia;  ac  per  hoc  illa  relatio  nullo  modo  sit  prior  naturaliter  principiato”;  Scotus,  Meta.,  9.5,  n.  15  (OPh,  4:  564.22-­‐24):  “Sic  numquam  aliquid  est  activum  nisi  naturam  sit  habere  ordinem  ad  aliquid  extra  se;  nec  tamen  ille  ordo  essentialis  est  activo  (ut  modo  loquimur),  hoc  est,  in  quantum  est  prius  naturaliter  acto”;  Scotus,  Meta.,  9.5,  n.  17  (OPh,  4:  565.9-­‐14):  “Ad  illud  quod  additur  de  potentiis  animae,  dicitur  quod  si  ‘potentia’  intelligatur  aggregatum  ex  absoluto  et  respectu,  isto  modo  distinguitur  per  respectus  formaliter.  Sed  sic  non  sunt  priores  naturaliter  actibus,  proportionaliter  accipiendo  respectus  principii  in  anima  et  in  actibus  respectus  principiati,  scilicet  si  actu,  actu;  si  potentia,  potential.”  32  Scotus,  De  Primo,  1.8  (Wolter,  5):  “Secundo  modo  prius  dicitur,  a  quo  aliquid  dependet,  et  posterius,  quod  dependet.  Huius  prioris  hanc  intelligo  rationem,  quam  etiam  Aristoteles  5  ̊  Metaphysicae  testimonio  Platonis  ostendit:  Prius  secundum  naturam  et  essentiam  est  quod  contingit  esse  sine  posteriori,  non  e  converso.  Quod  ita  intelligo,  quod,  licet  prius  necessario  causet  posterius  et  ideo  sine  ipso  esse  non  possit,  hoc  tamen  non  est  quia  ad  esse  suum  egeat  posteriori,  sed  e  converso;  quia  si  ponatur  posterius  non  esse,  nihilominus  prius  erit  sine  inclusione  contradictionis.  Non  sic  e  converso,  quia  posterius  eget  priore,  quam  indigentiam  possumus  depen-­‐  dentiam  appellare,  ut  dicamus  omne  posterius  essentialiter  a  priore  necessario  de-­‐  pendere;  non  e  converso,  licet  quandoque  necessario  posterius  consequatur  istud”;  Ord.,  2.1.4–5,  n.  262  (Vat.  7:  129.12–17):  “quia  impossibilitas  quod  a  sit  sine  b  aut  est  propter  identitatem  b  ad  a,  aut  propter  prioritatem,  aut  simultatem  in  natura;  igitur  si  b  non  

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the  case  at  hand,  for  Scotus  wants  to  insist  that  the  basis  for  activity  can  exist  without   that   activity.   And   indeed,   there   are   plenty   of  wine   glasses   that   do  not  shatter.33    

There   are   two   points   of   clarifications   to   make   here.   The   idea   that  connections   presuppose   the   things   they   connect  means   first   of   all   that,   in  order  for  some  A  and  B  to  be  connected,  A  and  B  must  exist.  There  cannot  be  a  connection  between  A  and  B   if  either  of  A  or  B  are  not   there.  Plato  could  not  be  the  pupil  of  Socrates  if  there  were  no  Socrates.  And  likewise  for  wine  glasses  and  fragility:  although  there  are  times  when  glasses  do  shatter  (like  when   I  drop   them),  what  about   the   times  when   they  do  not   shatter?  What  about,   say,   when   I   hold   a   wine   glass   firmly   in   my   hand,   or   when   it   sits  undisturbed  in  the  cupboard?  Isn’t  the  glass  fragile  then?    

As   Scotus   sees   it,  Henry  would  have   to   say  no,   because  Henry  believes  that   a   connection  with   shattering   is  essential   to   fragility,   in  which   case   the  glass  could  not  be  fragile  without  that  connection.  But  how  could  there  be  a  “connection”   with   shattering   if   there   is   no   shattering   going   on?   Surely   a  connection   with   a   non-­‐existent   activity   is   not   a   real   connection.   It   would  seem,  then,  that  when  there  is  no  shattering  going  on,  the  glass  would  not  be  able  to  satisfy  the  essential  conditions  that  Henry  thinks  are  required  for  it  to  be  fragile,   in  which  case  Henry  would  have  to  admit  that  the  glass  is  not  fragile  when  it  is  not  shattering.  But  that,  Scotus  thinks,  is  absurd,  for  surely  the  glass  is  still  fragile,  even  when  it  is  not  shattering.    

A  follower  of  Henry  might  respond  by  saying  something  like  this:  “Well,  of  course  the  glass  is  not  connected  to  an  actual  event  of  shattering,  but  it  is  connected   to   a   potential   event   of   shattering,   for   if   it   could   not   shatter,   it  would  not  be  fragile.”  But  what  exactly  is  a  “potential”  event  of  shattering?  Is  it  like  a  ghostly  version  of  the  real  thing?  Is  it  some  other  glass  shattering  in  another  world?  Where  are  these  “potential”  shatterings  located?  Somewhere  in  the  glass?  Do  they  have  parts  or  take  up  space?  All  of  this  pushes  Henry  to  clarify  exactly  what  it  is  that  bases  must  be  so  essentially  connected  to.  

                                                                                                                                                                                                                                                                                   sit  prius  naturaliter  quam  a,  nec  necessario  simul  natura,  et  a  non  potest  esse  absque  b,—sequitur  quod  a  sit  idem  b:  si  enim  sit  aliud  et  posterius  eo,  non  est  verisimile  quod  naturaliter  non  possit  esse  sine  eo  absque  contradictione.”  Note,  however,  that  some  a’s  being  able  to  exist  without  some  b  but  not  vice  versa  is  only  a  sufficient  condition  (not  a  necessary  condition)  for  a’s  being  naturally  prior  to  b.  This  is  important,  because  for  Scotus,  some  entities  in  the  Godhead  are  naturally  prior  to  others,  even  though  everything  in  the  Godhead  is  necessary.  33  Scotus,  Meta.,  9.5,  n.  10  (OPh  4:  562.2–6):  “nam  illa  [viz.  relatio  principii  principiantis  in  actu]  simul  natura  est  cum  principiato  in  quantum  principiatum,  cum  sint  correlativa,  et  posterior  est  natura  eo  quod  est  principiatum,  hoc  est,  illo  in  quo  fundatur  relatio  principiati;  quia  relatio  principiati,  quae  simul  est  cum  relatione  principiantis  in  actu,  posterior  est  eodem,  quod  scilicet  est  principiatum”;  ibid.,  n.  13  (OPh  4:  563.11–14):  “Sed  ab  absoluto  [principio],  sine  omni  respectu  praecedente,  est  effectus  absolutus;  quo  posito,  posterius  natura  sequitur  relatio  actualis  mutual  principiati  ad  principium,  quae  in  neutro  esse  potuit,  altero  extremo  non  posito”;  ibid.,  n.  12  (OPh  4:  562.22–23):  “ac  per  hoc  illa  relatio  nullo  modo  sit  prior  naturaliter  principiato.”  

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Furthermore  —  and  this   is  the  second  point  of  clarification  I  wanted  to  make   —   the   idea   that   connections   presuppose   the   things   they   connect  means   not   only   that   A   and   B   must   exist   in   order   to   be   connected,   it   also  means  they  must  be  constituted  in  all  the  right  ways  too.  If  some  A  and  B  are  connected,   then   they  must  already   have  all   the  parts   and   constituents   that  are   required   to   be   connected   in   that  way.   The   connection   itself   cannot   be  one  of  those  required  parts  or  constituents.34    

That   is   why   if   parents   have   children,   we   can   safely   assume   that   they  must  have  been  fertile.  Having  children  did  not  make  them  fertile,  it  did  not  add   some   essential   ingredient   that   they  needed  beforehand   in   order   to   be  fertile.  On  the  contrary,  they  must  have  already  been  fertile  in  order  to  have  children   in   the   first   place.   Likewise,   if   I   drop   a  wine   glass   and   it   shatters,  surely   it  was  already  fragile.  Shattering   it  did  not  make   it   fragile.  Whatever  the  ingredients  are  that  glass  needs  to  be  fragile,  it  already  had  them  prior  to  being  shattered.35    

It  is  also  worth  noting  that  connections  do  not  explain  very  much,  for  the  very  same  reasons  that  were  just  mentioned.  For  as  Scotus  points  out,  if  you  asked  me  why  two  white  things  are  similar,  it  wouldn’t  help  me  much  if  you  told  me  “because  they  are  similar.”  But  it  would  help  me  if  you  said  “because  they   are   both   white,”   for   then   you   would   be   appealing   to   the   basis   of  similarity.36   And   the   same   goes   for   powers.   To   recall   the   famous   quip   by  Molière,   if   I   asked  you  why  opium  makes  me   sleepy,   it  would  not  help  me  much   if   you   said   “because   it  makes   you   sleepy.”37  But   it  would  help   if   you  

                                                                                                               34  Scotus,  Meta.,  9.5,  n.  9  (OPh  4:  561.22–24):  “Manet  autem  in  principio  quando  principiat  quidquid  est  de  ratione  eius  in  quantum  est  prius  naturaliter  principiato”;  ibid.,  n.  10  (OPh  4:  562.6–8):  “Oporteret  autem  relationem  intrinsecam  potentiae  activae  esse  priorem  natura  illo  quod  est  principiatum  [si  relatio  determinaret  poten-­‐  tiam  activam,  sed  tale  est  impossibile].  Ergo  omnino  nulla  relatio  invenitur  talis  [in  principio  priore  naturaliter  principiato]”;  ibid.,  n.  13  (OPh  4:  563.7–11):  “Hoc  modo  intelligendo  quaestionem,  dicitur  quod  nihil  est  de  ratione  potentiae  nisi  absoluta  aliqua  essentia,  in  qua  immediate  fundatur  aliquis  respectus  ad  principiatum,  ita  quod  nullus  respectus  praecedit  in  actu  ipsam  principiationem  per  quam  quasi  determinetur  ad  principiandum.”  35  And  the  sense  of  “already”  here  does  not  have  to  temporal,  as  Scotus  makes  clear,  Meta.,  9.5,  n.  14  (OPh  4:  564.1–6):  “Nec  potest  dici  quod  una  tantum  praecedat  aliam  tempore,  quia  patet  quod  agens,  habens  actionem  coaevam  sibi,  ita  determinatur  ad  agendum  et  habet  quidquid  requiritur  ad  talem  determinationem  sicut  agens  praecedens  tempore  suam  actionem.  Ergo  relatio  determinans—si  qua  est—non  oportet  quod  praecedat  tempore,  sed  tantum  natura.”  36  Scotus,  Lect.,  1.7.un.,  n.  35  (Vat.  16:  485.9–21):  “Unde,  quando  quaerimus  in  quo  sunt  aliqui  similes,  non  quaerimus  in  quo  sunt  similes  per  se  primo  modo,  quia  sic  similitudine  sunt  similes,  sed  quaerimus  in  quo  sunt  similes  secundo  modo  per  se,  utrum  sint  similes  albedine  vel  alia  forma;  unde  quaerimus  de  fundamento  similitu-­‐  dinis.  Similiter  quando  quaeritur  quid  sit  potentia  animae,  non  quaeritur  de  respectu  quem  potentia  importat,  sed  quaeritur  de  fundamento”  (on  this,  see  also  Meta.,  9.3–4,  n.  19  (OPh  4:  543.1–8)).  37  Molière,  Le  Malade  Imaginaire  (in  The  Dramatic  Works  of  Molière,  3  volumes,  translated  by  Henri  van  Laun  (Philadelphia:  Gebbie  &  Barrie,  Publishers,  1879),  3:  567):  “Mihi  à  docto  doctore.  Domandatur  causam  et  rationem  quare  Opium  facit  domire.  A  quoi  respondeo;  Quia  est  in  eo  Virtus  dormitiva,  Cujus  est  natura  Sensus  assoupire.”  

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pointed   to,   say,   chemical   and   physiological   factors   that   are   the   basis   for  opium’s  ability  to  make  me  sleepy.    

For   Scotus   then,   the   connection  between  bases   and   their   activities   just  cannot  be  an  essential  ingredient  in  making  those  bases  the  bases  that  they  are.  Connections  show  up  on  the  explanatory  seen  too  late,  as  it  were,  to  play  any  constitutive  role.  The  basis   for  any  activity  must  already  be  capable  of  empowering   activity   in   and   of   itself,   without   the   need   for   any   connection  with  activity.  So,  Scotus  concludes,  powers  are  just  the  parts,  materials,  and  other  constituents  that  activities  directly  spring  forth  from.38    

And   that,   I   take   it,  means   Scotus  has   a   “one-­‐category”   ontology.  Unlike  Aquinas’s   “two-­‐category”   ontology,   which   postulates   categorical   and  dispositional  entities  as  distinct   classes  of   things,   and  unlike  Henry’s   “two-­‐aspects”  ontology,  which  holds  that  things  can  have  both  a  categorical  and  a  dispotional  aspect,  Scotus  thinks  there  are  just  categorical  things:  there  are  just   the  parts,  materials,  and  other  constituents   that   things  are  made   from,  and  that  is  all  there  is  to  it.  “Powers”  or  “dispositions”  are  nothing  more  than  the  particular  parts,  materials,  or  other  (categorical)  constituents  that  cause  the  effects  in  question.39    

   

William  Ockham    

Like   Scotus,   Ockham   rejects   Henry’s   claim   that   bases   essentially   include   a  connection  with   their   activities,   and   his   reasons   for   this   are   very   close   to  Scotus’s.   Ockham   begins   by   pointing   out   that   if   bases   did,   in   fact,   require  some  sort  of  connection  with  their  activities,  then  those  connections  would  either  have  to  be  mere  conceptual  connections   that  we  draw  in  our  minds,  or  they  would  have  to  be  real  connections.40  Unfortunately,  neither  option  is  any  good.    

As   for   conceptual   connections,   the   problem   with   them   is   that   nature  rarely  cares  what  you  or  I  may  think  about  it.  I  may  be  able  to  draw  all  sorts  of  connections  between  things  in  my  mind,  but  the  natural  world  is  going  to  

                                                                                                               38  Scotus,  Meta.,  9.5,  n.  13  (OPh,  4:  563.7-­‐12):  “Hoc  modo  intelligendo  quaestionem,  dicitur  quod  nihil  est  de  ratione  potentiae  nisi  absoluta  aliqua  essentia,  in  qua  immediate  fundatur  aliquis  respectus  ad  principiatum,  ita  quod  nullus  respectus  praecedit  in  actu  ipsam  principiationem  per  quam  quasi  determinetur  ad  principiandum.  Sed  ab  absoluto,  sine  absoluto,  sine  omni  respectu  praecedente,  est  effectus  absolutus.”  39  This  is,  I  think,  significant  for  Scotus’s  theory  of  causation.  For  it  becomes  clear  in  this  context  that  Scotus  thinks  the  parts,  materials,  and  constituents  that  we  refer  to  as  powers  are  really  nothing  more  than  the  efficient  causes  of  the  effects  in  question.  Whereas  someone  like  Aquinas  would  say  a  power  is  that  “through  which”  an  agent  causes  an  effect,  Scotus  would  say  the  power  just  is  the  agent  that  causes  the  effect.  Ockham  too  holds  this  view,  and  it  is  likely  that  Henry  does  too.    40  As  Ockham  explains  about  the  mind’s  powers,  Quaest.  in  Sent.,  2.20  (OTh,  5:  432.5-­‐6):  “Si  in  anima  esset  talis  respectus  [ad  actum],  aut  est  respectus  realis  aut  rationis.”  

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do  what   the  natural  world   is  going   to  do,   irrespective  of  whatever  sorts  of  conceptual  connections  I  might  make.    

Of  course,  the  connections  we  draw  in  our  minds  can  affect  our  behavior.  For   instance,   if   I   mistakenly   identify   the   person   entering   the   room   as   a  horrible   monster,   my   screaming   and   tripping   out   the   back   door   would  certainly  be   the   result   of   the  misidentification   I  made   in  my  mind.  But   the  point   here   is   that   even   though   connections   drawn   in   our  minds   can   affect  our   behavior,   they   do   not   affect   the   behavior   of   other   things   like   glass,  flames,  and  the  like.  Moreover,  glass,  flames,  and  the  like  do  not  have  minds  anyway,   so   they   cannot   have   anything   “in   mind”   that   might   affect   their  behavior  either.    

Consequently,   any   connection   I   might   draw   in  my  mind   between,   say,  glass   and   shattering   is   not   going   to   have   any   affect   on   the   fragility   of   the  glass.   Whether   I   think   the   glass   can   shatter   or   not   makes   no   difference.  Either  it  can,  or  it  can’t,  but  that  has  nothing  to  do  with  my  thoughts  about  it.  And  of  course,  my  thoughts  and  ideas  could  never  become  essential  parts  of  the  glass’s   fragility,   for   thoughts  and   ideas   just  cannot   leap  out  of  my  head  and  jump  into  the  glass.41  

So,   if   bases   essentially   require   some   sort   of   connection   with   their  activities  (as  Henry  claims),  those  connections  will  therefore  have  to  be  real  connections.  But  Ockham  thinks  real  connections  fare  no  better  here  either,  and   the   reason   is   that,   as   Scotus   already   pointed   out,   connections  presuppose  the  things  they  connect,  not  the  other  way  around.42    

To  highlight  this  point,  Ockham  asks  us  to  imagine  what  would  happen  if  God  created  you   in  a  world  all  by  yourself.  There  would  be  nothing  else   in  that  world  except  for  you;  you  would  just  be  floating  there,  so  to  speak.  Now,  since   there  would   be   nothing   else   in   the  world   to   think   about,   you  would  presumably   not   be   able   to   think   about   things   like   trees   or   stop   signs.  Nevertheless,   Ockham   wonders,   wouldn’t   you   still   be   capable   of   thinking  about   trees   or   stop   signs,   if   for   some   reason   you   were   ever   to   come   in  contact  with  them?  Ockham  thinks  the  answer  would  have  to  be  yes,  and  he  thinks  it  goes  to  show  that  whatever  it  is  that  makes  you  capable  of  thinking  about  trees  and  stop  signs  does  not  depend  on  you  actually  doing  so.43    

But  suppose  someone  were  to  object  here  and  say  that  you  couldn’t  think  about  trees  and  stop  signs  while  floating  in  the  world  all  by  yourself.  At  this  

                                                                                                               41  Ockham,  Quaest.  in  Sent.,  2.20  (OTh,  5:  432.6-­‐8):  “Non  [est  respectus]  rationis,  quia  ille  est  per  actum  intellectus  comparantis.  Sed  ante  omnem  actum  intellectus  sunt  potentiae  in  essentia  animae  perfecte.”  42  Ockham,  Quaest.  in  Sent.,  2.20  (OTh,  5:  432.8-­‐10):  “Nec  est  respectus  realis,  quia  nunquam  est  respectus  realis  sine  termino  realiter  exsistente,  secundum  eum  etiam  [viz.,  secundum  Henricum].”  43  Ockham,  Quaest.  in  Sent.,  2.20  (OTh,  5:  432.10-­‐12):  “Sed  potentiae  animae  possunt  esse  perfectae  et  nullum  obiectum  [esse],  quia  Deus  potest  facere  animam  intellectivam  non  faciendo  aliquod  obiectum  in  mundo.  Et  tunc  erunt  potentiae  animae  perfectae,  et  tamen  nullus  terminus  in  actu,  quia  nullum  obiectum.”  

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point,  we  could  respond:  why  not?  In  Ockham’s  defense,  we  might  press  for  an  explanation.  Suppose  we  compare  your  mind  in  the  floating  world  to  your  mind   in   the   regular  world,  where   there   are   trees   and   stop   signs.   Suppose  also   that   there   is   no   qualitative   difference   in   composition   or   constitution  between  your  mind  in  the  floating  world  vs.  your  mind  in  the  regular  world.  The  only  qualitative  difference  between  the  two  is  that  in  the  regular  world  you  actually  think  about  trees  and  stop  signs,  whereas  in  the  floating  world  you  do  not.    

Given   that,   could   we   reasonably   say   that   you   are   really   incapable   of  thinking  about  trees  and  stop  signs  in  the  floating  world?  Would  it  really  be  plausible  to   insist   that   the  mere  connection  our  minds  have  with  trees  and  stops  signs  in  the  regular  world  is  enough  to  make  them  capable  of  thinking  about   trees   and   stop   signs?   Surely   not.   Surely   your  mind  would  be   just   as  capable   of   thinking   about   trees   and   stop   signs   in   the   floating   world   as   it  would  be  in  the  regular  world,  especially  given  the  fact  that  the  two  are  in  all  other  respects  the  same.    

In  the  end  then,  Ockham  agrees  with  Scotus,  for  like  Scotus,  he  would  be  happy   to   say:   of   course   there   are   connections   between   bases   and   their  activities  —  when  those  bases  are  actually  causing  the  activities  in  question.  But   those   connections   cannot   play   any   role   in   the   constitution   of   those  bases.  The  parts,  materials,  and  other  constituents  that  cause  the  activities  in  question  must  be  able  to  cause  those  activities  prior  to  actually  doing  so,  and  that  is  all  that  powers  are.    

   Conclusion    

In   all   of   this,   I   think   we   can   identify   three   separate   ontologies   of   powers  here.   Aquinas   is   what   we  might   call   a   “two-­‐category”   theorist.   That   is,   he  thinks  there  are  categorical  entities  in  the  world,  and  there  are  dispositional  entities.  Hence,   Aquinas  would   insist   that   there   are   substances,   quantities,  and   qualities,   which   are   categorical   in   nature,   but   there   are   also   powers,  which  are  special  kinds  of  qualities  that  are  dispositional  in  nature.    

The   key   is   that   Aquinas   is   not  willing   to   reduce   powers   to   categorical  entities.   As   he   sees   it,   considerations   about   identity   (or   rather,   the   lack  thereof)   are   just   too   strong.   However   tempting   it   may   be   to   think   of  categorical   and   dispositional   entities   as   the   same,   they   just   cannot   be  identical,  because  there  are  some  things  that  are  true  of  the  one  that  are  not  true  of  the  other.    

Henry,   by   contrast,   refuses   to   admit   that   powers   are   distinct   entities  over  and  above  their  bases,  for  otherwise  we  would  have  an  infinite  regress.  Hence,  when  we   talk  about  powers  and  dispositions,  Henry   insists   that  we  are  not  referring  to  or  picking  out  some  special  kind  of  entity  over  and  above  the   parts,   materials,   and   other   constituents   that   activities   are   based   on.  

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Rather,   we   are   referring   to   or   picking   out   just   those   categorical   parts,  materials,  and  other  constituents  that  the  activities  in  question  are  based  on.    

Nevertheless,   Henry   thinks   those   categorical   entities   have   their   own  identities  and  natures  when  considered  in  and  of  themselves.  They  serve  as  powers   only   insofar   as   they   are   connected   to   the   activities   for  which   they  are  the  basis.  In  and  of  itself,  glass  is  just  glass,  but  insofar  as  it  is  connected  to  shattering,  it  is  the  basis  for  fragility.  And  this,  I  take  it,  tells  us  that  Henry  is   what   we   might   call   a   “two-­‐aspects”   theorist,   for   Henry   thinks   that   the  various   parts,   materials,   and   other   constituents   in   the   world   can   be   both  categorical  and  dispositional  in  nature.    

Scotus   and   Ockham,   however,   are   what   we   might   call   “one-­‐category”  theorists,   for   they   reduce  powers   to   categorical   entities   entirely.  When  we  talk  about  powers,  we  are  referring  only  to  the  categorical  parts,  materials,  and  other  constituents  of  things.  We  are  not  referring  to  some  special  kind  of  entity   as   Aquinas   would   say,   nor   are   we   referring   to   those   parts   and  materials   under   some   special   mode   or   respect.   Rather,   we   are   simply  referring  to  those  categorical  parts  and  materials,  and  that  is  all  we  mean  by  “powers”  and  “dispositions.”