Democracy and good governance require politicians to engage in reasoned debate, informed decision making and measured judgements. This presupposes rationality. Is this always true?
South Africa's energy sector is perhaps at its most fluid and unpredictable stage it has ever been in.
South Africans are all poorer as a result of Jacob Zuma's decision to replace his finance minister. But there maybe benefits too. The debacle suggests his grip on power has been weakened.
South Africa has had three finance ministers in four days. President Jacob Zuma will live with the fall-out for the rest of his term. Markets have a long-term memory and won't easily forget.
Academics from several South African universities say that in the current world economy decisions about any country's finance minister cannot be made "lightly or capriciously".
President Jacob Zuma's era has been characterised by a high turnover, not only of cabinet members, but also senior public officials and executives in state-owned enterprises.
The sudden expulsion of the finance minister makes it hard not to be pessimistic about the South African government's ability to manage the difficult challenges it might face in 2016.
It is difficult to analyse political developments in South Africa. Decision-making does not fit any neat political science theory. President Zuma is unpredictable and his policy thinking is woolly.
The removal of Minister Nene is a significant act. The fact that he has been replaced by someone who is unknown and untested simply compounds it.
Credit rating agencies have come in for a lot of flack. But the bottom line is that to attract investors with deep pockets countries can't avoid having a credit rating. And a good one at that.