Thought it would be interesting to hear opinions on this.
Lets consider a hypothetical. If it were possible to take 1000 people considered to be 'evil' who committed terrible crimes such as murder during their lives and rewind time to when they were born. The 1000 people are then born and raised by strong, caring parents who provide positive role models and instil good values in the individuals.
It is reasonable to assume that not all the 1000 would then go on to commit the terrible crimes they would have in their other reality.
Factors like surroundings, socialisation, opportunities, the general situation and a strong support network make a big difference. The power of the situation has been shown in many sociological studies such as the 'Zimbardo prison experiment'.
So considering the people deemed previously as 'evil' but who would not have committed these crimes if they had a better upbringing. Were they in fact 'evil' or are they simply a product of their environment? If they are simply a product of their environment does this change how society should punish/treat/rehabilitate them in regards to the crimes they have committed?
To put it another way, you could take someone who has done a lot of great work in their life and significantly benefited society. If this person had been brought up alternate circumstances they may not have developed as well psychologically and then may have led a life deemed as 'evil' and committed heinous crimes. So were they indeed 'evil' or did society fail them? In the second example should a more compassionate rehabilitory approach be taken when dealing with them?