Cri$cal  thinking:  Essen$al  concepts    

Fact:    something  which  can  be  demonstrated  to  be  true  

   

 

Building  Blocks  of  Cri0cal  Thinking    

Fact:    something  which  can  be  demonstrated  to  be  true  

 Asser$on:  

 something  that  is  held  to  be  true,  but  which  has  not  been,  or  cannot  be,  actually  demonstrated  to  be  true  

   

 

Building  Blocks  of  Cri0cal  Thinking    

Fact:    something  which  can  be  demonstrated  to  be  true  

 Asser$on:  

 something  that  is  held  to  be  true,  but  which  has  not  been,  or  cannot  be,  actually  demonstrated  to  be  true  

 Opinion:  

 something  that  is  believed  to  be  true  by  the  speaker,  but  which  may  or  may  not  be  shared  by  others  

 

Building  Blocks  of  Cri0cal  Thinking    

Theory  

A  theory  is  our  best  a9empt  to  explain  something  in  the  natural  world,  based  on  what  we  currently  know.  

“A  theory  is  an  explana$on”  

“A  theory  is  an  explana>on,  based  on  our  current  understanding  of  the  natural  world”  

Essen0al  Concepts  in  Cri0cal  Thinking    

Theory  

A  theory  is  our  best  a9empt  to  explain  something  in  the  natural  world,  based  on  what  we  currently  know.  

“A  theory  is  an  explana$on”  

“A  theory  is  an  explana>on,  based  on  our  current  understanding  of  the  natural  world”  

Essen0al  Concepts  in  Cri0cal  Thinking    

A  theory  is  not  fixed  and  unchanging:    it  can  con>nue  to  evolve  and  improve,    as    we  discover  new  facts  about  the  natural  world.  

Compe$ng  theories  

The  value  and  usefulness  of  a  theory  is  measured  only  by  how  well  it  corresponds  with  reality.  

ODen  several  different  theories  may  try  to  explain  the  same  aspects  of  the  natural  world  –  compe0ng  theories  

So  how  can  we  judge  how  good  a  theory  is?  

Essen0al  Concepts  in  Cri0cal  Thinking    

How  good  is  a  theory?  There  are  two  essen>al  requirements  for  a  viable  theory:  

•  A  good  theory  is  supported  by  evidence,  from  our  current  knowledge  of  the  natural  world  

Essen0al  Concepts  in  Cri0cal  Thinking    

How  good  is  a  theory?  There  are  two  essen>al  requirements  for  a  viable  theory:  

•  A  good  theory  is  supported  by  evidence,  from  our  current  knowledge  of  the  natural  world  

•  A  good  theory  must  make  testable  (“falsifiable”)  predic$ons.  

A  hypothesis  is  a  predic>on,  based  on  a  theory,  which  can  be  verified  as  being  either  correct  or  incorrect.  

Essen0al  Concepts  in  Cri0cal  Thinking    

How  good  is  a  theory?  

The  value  and  usefulness  of  a  theory  are  measured  only  by  how  well  the  theory  corresponds  with  reality:  hypotheses  (predic>ons)  based  on  a  good  theory  will  consistently  be  proved  correct.    

If  a  theory  makes  a  hypothesis  that  is  incorrect,  then    

•  Either  the  theory  must  change  and  evolve,  in  order  to  correspond  be9er  with  reality  

   

•  Or,  if  the  theory  cannot  change  in  this  way,  it  must  be  discarded,  and  a  new  explana>on  must  be  found.  

Essen0al  Concepts  in  Cri0cal  Thinking    

The  nature  and  importance  of  evidence  

Asser0ons  Opinions  

Facts  

Theory  

Testable  Hypothesis  (predic$on)  

Evidence  

May  support  the  hypothesis,  and  rule  out  (disprove)  other  hypotheses  

May  lead  to  a  new  and  revised  hypothesis,  which  can  be  tested  again  

May  be  inconclusive,  so  that  no  firm  conclusions  can  be  made  

May  disprove  the  hypothesis,  so  that  the  theory  needs  to  be  revised  or  discarded  

Essen0al  Concepts  in  Cri0cal  Thinking    

Evidence  is  the  proof  (facts,  experimental  results,  observa>ons)  that  supports  the  argument.  

An  argument  is  a  set  of  logical  statements,  leading  to  a  fair  conclusion,  with  reasons  offered  to  support  the  conclusion.  

A  conclusion  is  a  reasoned  inference  or  deduc>on  that  follows  from  the  logic  of  the  argument.  

Essen0al  Concepts  in  Cri0cal  Thinking    

It  is  a  skill  to  present  your  own  arguments  in  a  persuasive  and  logical  way,  and  to  hear  and  take  on  board  the  arguments  of  

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