It is not difficult for a liberal to praise this fine book by the Hoover Institute's Thomas Sowell. Sowell shows how part of the disconnect between most liberals and conservatives rests with their subscribing to different concepts of human nature. These different concepts then color our perceptions, causing us to define issues in different ways that play havoc with our ability to effectively communicate with each other. Everyone interested in politics can find useful concepts here.
Sowell's divide is between what he calls the constrained, versus the unconstrained, vision, and like all good scholars, he recognizes that neither vision could lead to human flourishing without some admixture from its complement. Sowell takes up this divide, starting in the 18th century, without mentioning its roots in theological debates of the 5th century when Augustine and Pelagius covered much of the same ground. But Sowell's concern is the modern world, where the realms of politics and economics are privilaged, for it is in these realms that he traces how the divide plays out.
The constrained version is the idea that human endeavor is limited and often mistaken, that no amount of human effort or knowledge can lead to unmitigated goods. Hence Adam Smith and laissez faire economics, Hamilton and limited government, Holmes and limited morality from the bench, Burke and limited political change.
The unconstrained version is based on the idea that people can know the good and do it. Education and research are the backbones of this absolute. In this reviewer's opinion, here Sowell's offering of exemlers such as William Godwin and Marx, who were unpleasant, often irresponsible human beings, shows a slight tendency to setting up paper tigers. It is not hard to show Godwin as profoundly mistaken. But what of Abraham Lincoln?
Sowell also never fully explains how conservatives can be so adamant that it is equality of processes, not equality of results, that matters. For what human being does not naturally allow at least part of his or hers judgement to be touched by results? It goes against common sense to never take results into account.
In short, Sowell sets up two absolutes that do not really exist in complete purity(as he himself admits.) It is in the admixture of the two that real growth can occur. It is interesting that the Judeo-Christian ethos, which has survived for over 3,000 years, includes just such a mix. On one hand, there is the realization that man is not perfect, nor perfectable by his or her own powers. But there is also the affirmation of a prophetic vision of greater justice and mercy(and salvation through a messiah,) that should be attended to here in this imperfect world. The longevity of this vision, and its ability to birth and nurture Western civilization, perhaps argues for the need to understand the limited validity of both end's of Sowell's polarities, if either is taken as the last word on truth.