Psychologists suggest that to cure cruelty

Darwin's theory of evolution

1. 
   failed to be understood clearly because it wasn't well supported with facts
   
2. 
   was eventually admitted, although it had been severely attacked at first
   
3. 
   was difficult to defend because of its unanswerable points
   
4. 
   was regarded as a great success on scientific grounds
   

2. Darwin ...

1. 
   replied to the criticism only of those who attacked his theory scientifically
   
2. 
   was discouraged when he received such severe attacks from the scientists
   
3. 
   was an anti-Christian who had been trying to alter the moral values of society
   
4. 
   was able to find only a few supporters with his theory of evolution