Individuals  differ  greatly  in  their  gifts  and  ca-
pacities, such  differences  being  both  quantitative
and  qualitative.  Thus  in  general  there  are
three  classes  of  individuals,  differing  quantita-
tively   with   respect   to   their   general    mental


161


AQUATICS


AQUINAS


equipment.  They  are  the  talented  or  gifted
persons;  the  average  person,  or  person  of
medium  ability;  and  the  subnormal.  Within
each  of  these  classes  there  are  various  sub-
classes. This  is  especially  true  of  the  last
class,  which  comprises  those  who  are  weak-
minded  and  those  who  are  merely  lacking  in
mental  ability  though  below  the  average  in
capacity.  The  former  are  still  further  sub-
divided into  the  idiots  and  imbeciles,  who  differ
somewhat  in  the  degree  of  their  mental  ability.
The  mental  and  physical  qualities  giving  rise
to  differences  in  aptitude  are  difficult  to  dis-
tinguish. Apparently  differences  in  the  purely
sensory  basis  of  the  mental  life  are  compara-
tively insignificant,  as  is  shown  by  the  fact  that
many  persons  deprived  of  some  of  their  senses
reach  a  high  degree  of  mental  development.
On  the  other  hand,  it  is  probable  that  a  natural
tendency  to  emphasize  the  reproduced  elements
of  one  or  another  of  the  spheres  of  sense  may  be
at  the  basis  of  many  aptitudes  which  express
themselves  in  choice  of  callings  and  talented
performance.  Fundamental  differences  of  this
sort,  for  example,  are  often  at  the  basis  of  the
high  degree  of  perfection  attained  by  artists,
musicians,  etc.
Another  fundamental  group  of  differences  in
mental  qualities  are  differences  in  attention
which  to  a  large  extent  govern  a  person's
mental  aptitudes.  The  type  of  a  man's  atten-
tion (distributive  or  intensive,  etc.)  has  un-
doubtedly a  great  influence  upon  the  direction
taken  by  his  mental  development.        E.  H.  C.
References  :  —
Meumann,     E.     Experimentelle     Pildogogik,     Vol.     I.
