Why is there the usual political partisanship? Thomas Sowell (Part 2)

Part 1 here.

On the constrained and unconstrained visions.

Thomas Sowell : "with visions it is different. These are the implicit assumptions with which you operate. You may not articulate them even to yourself, but you are assuming certain things when you talk or when you think. Seldom are those things spelled out."

Sowell's 'visions' are basically views about two things: human nature and social knowledge. 

To take human nature first: the constrained vision has a sober and unsentimental view about it. It holds that human nature is essentially fixed – people are as we find them, exhibiting a mixture of motives, some social and some anti-social. Thus, if it is to succeed, public policy has to run with the grain of human nature as we know it and to avoid assuming that it will change in such a way as to help policy to succeed. This means that, in order to improve society, we must focus on institutions and try to understand the incentives people have to behave in social or anti-social ways. 

The unconstrained vision, by contrast, is optimistic about improving human nature. It sees people as naturally social and perfectible. Public policy is therefore not a matter of incentives but of freeing people to realise their natural, and naturally good, selves and educating them to conform to a new order.

A quite concise summary helpfully provided by New Zealand?

Finally, Thomas Sowell provides useful real life historical examples. The American Revolution and the French Revolution.

Well in France the idea was that if you simply put the right people in charge and created the right institutions, then all these problems would go away. In the United States, it was assumed from the outset that there were very limited things you could do and what you needed to do above all was to minimize the damage done by the flaws of human nature. This is why the United States for example has the Constitution, so much lamented by some of those who believe in the French Revolution in which this group is offset by that group and nobody can sort of run wild. If you believe that what you need is to have the right leaders who love the people and so on, a Messiah as it were, then your problems are solved. But if you do not believe there is any political Messiah, and you believe that you have to make sure that all people are restrained in what they are able to do, then you have the separation of power, you have elections, you have Constitutions, you have all kinds of things hemming you in. According to Houssay who was a great supporter of the French Revolution, could not understand why there was this separation of powers. Not even when at the end of his life, he was arbitrarily thrown into prison where he continued to write about why the Americans have this separation of power. And of course if there is going to be a separation of power he would not be rotting in prison. 

In other words, in the constrained vision, human nature = good. In the unconstrained vision, human nature = bad.