Dialectics - it's important to study dialectics itself (Mao, Hegel etc.) because this creates an awareness or sensitivity to possibilities of things turning into their opposite that we otherwise might not even notice - it has the potential to make our thinking more fluid and flexible.
The link below will take you to a forum discussion about dialectics.
The link address is: http://www.lastsuperpower.net/disc/members/850249180673/