Only  the  fourth  method  will  be  given  consideration  in
detail  at  this  point,  because  the  other  three  have  already
been  considered  at  length  in  the  preceding  chapters  on  Evi-
dence, Argument,  and  Fallacy.
Refutation  by  Special  Devices.  —  Special  devices  com-
monly employed  in  refutation  are  :

1 .  Turning  the  Tables  ;

2.  Reductio  ad  Absurdum;

3.  The  Method  of  Residues ;  and

4.  The  Dilemma.
Turning  the  Tables.  —  Turning  the  tables  is  a  form  of
refutation  in  which  an  opponent's  proof  is  overthrown  by
accepting  one  of  his  premises  and  from  it  establishing  the
opposite  conclusion.
An  illustration  of  this  method  of  refutation  is  found  in
the  following  argument  taken  from  a  daily  newspaper :

I.   The  argument  that :  —  A  high  protective  tariff  should  be
levied  on  lumber,  since  the  lumber   industry  needs   to

1  See  pages  61-62.
2  See  pages  101-103.
3  See  page  107,


126  Elements  of  Proof

be  encouraged,  because  the  lumber  supply  is  becoming

scarce,  —  is  unsound ;  for

A.   The  very  fact  that  the  lumber   supply  is   becoming

scarce  is  a  reason  for  not  levying  a  high  protective

tariff  on  lumber ;  for

1.  A  high  protective  tariff  would  result  in  still
further  depleting  our  native  lumber  supply;
and

2.  With  a  still  further  depleted  lumber  supply,  re-

sulting in  still  higher  prices  for  lumber,  a  com-
plete collapse  in  much  needed  building  projects
may  be  expected.
